Surges of advanced medical support associated with influenza outbreaks.

We utilized de-identified data to evaluate increases in four outcomes during influenza outbreak periods (IOPs) including: hospitalization, intensive care unit admission, mechanical ventilation or death for adults aged 18 years or older with medically attended acute respiratory illnesses (MAARI) admitted to any of Maryland's 50 acute-care hospitals over 12 years. Weekly numbers of positive influenza tests in the Maryland area were obtained from the US Center for Disease Control and Prevention interactive website. The fewest consecutive weeks around the peak week containing at least 85% of the positive tests defined the IOP. Weekly counts of individual study outcomes were positively correlated with regional weekly counts of positive influenza tests during all the IOPs over 12 years. Also, rate ratios comparing daily occurrences of each study outcome between the IOP and non-IOP were significantly elevated. These results confirm conclusions of previous studies that influenza outbreaks are clearly associated with deaths and increased use of advanced medical resources by patients with MAARI. These data analyses suggest that increased efforts to develop more effective influenza vaccines and therapeutics should be a priority.

Case-control study of paternal occupation and social class with risk of childhood central nervous system tumours in Great Britain, 1962-2006.

BACKGROUND: Paternal occupational exposures have been proposed as a risk factor for childhood central nervous system (CNS) tumours. This study investigates possible associations between paternal occupational exposure and childhood CNS tumours in Great Britain. METHODS: The National Registry of Childhood Tumours provided all cases of childhood CNS tumours born and diagnosed in Great Britain from 1962 to 2006. Controls without cancer were matched on sex, period of birth and birth registration sub-district. Fathers' occupations were assigned to one or more of 33 exposure groups. A measure of social class was also derived from father's occupation at the time of the child's birth. RESULTS: Of 11 119 cases of CNS tumours, 5 722 (51%) were astrocytomas or other gliomas, 2 286 (21%) were embryonal and 985 (9%) were ependymomas. There was an increased risk for CNS tumours overall with exposure to animals, odds ratio (OR) 1.40 (95% confidence intervals (CIs) 1.01, 1.94) and, after adjustment for occupational social class (OSC), with exposure to lead, OR 1.18 (1.01, 1.39). Exposure to metal-working oil mists was associated with reduced risk of CNS tumours, both before and after adjustment for OSC, OR 0.87 (0.75, 0.99).Risk of ependymomas was raised for exposure to solvents, OR 1.73 (1.02,2.92). For astrocytomas and other gliomas, risk was raised with high social contact, although this was only statistically significant before adjustment for OSC, OR 1.15 (1.01,1.31). Exposure to paints and metals appeared to reduce the risk of astrocytomas and embryonal tumours, respectively. However, as these results were the result of a number of statistical tests, it is possible they were generated by chance.Higher social class was a risk factor for all CNS tumours, OR 0.97 (0.95, 0.99). This was driven by increased risk for higher social classes within the major subtype astrocytoma, OR 0.95 (0.91, 0.98). CONCLUSION: Our results provide little evidence that paternal occupation is a significant risk factor for childhood CNS tumours, either overall or for specific subtypes. However, these analyses suggest that OSC of the father may be associated with risk of some childhood CNS cancers.

Case-control study of paternal occupation and childhood leukaemia in Great Britain, 1962-2006.

BACKGROUND: Paternal occupational exposures have been proposed as a risk factor for childhood leukaemia. This study investigates possible associations between paternal occupational exposure and childhood leukaemia in Great Britain. METHODS: The National Registry of Childhood Tumours provided all cases of childhood leukaemia born and diagnosed in Great Britain between 1962 and 2006. Controls were matched on sex, period of birth and birth registration subdistrict. Fathers' occupations were assigned to 1 or more of 33 exposure groups. Social class was derived from father's occupation at the time of the child's birth. RESULTS: A total of 16 764 cases of childhood leukaemia were ascertained. One exposure group, paternal social contact, was associated with total childhood leukaemia (odds ratio 1.14, 1.05-1.23); this association remained significant when adjusted for social class. The subtypes lymphoid leukaemia (LL) and acute myeloid leukaemia showed increased risk with paternal exposure to social contact before adjustment for social class. Risk of other leukaemias was significantly increased by exposure to electromagnetic fields, persisting after adjustment for social class. For total leukaemia, the risks for exposure to lead and exhaust fumes were significantly <1. Occupationally derived social class was associated with risk of LL, with the risk being increased in the higher social classes. CONCLUSION: Our results showed some support for a positive association between childhood leukaemia risk and paternal occupation involving social contact. Additionally, LL risk increased with higher paternal occupational social class.

Paternal occupation and neuroblastoma: a case-control study based on cancer registry data for Great Britain 1962-1999.

BACKGROUND: Neuroblastoma is the most common malignancy of infancy but little is known about the aetiological factors associated with the development of this tumour. A number of epidemiological studies have previously examined the risk associated with paternal occupational exposures but most have involved small numbers of cases. Here we present results from a large, population-based, case-control study of subjects diagnosed over a period of more than 30 years and recorded in the national registry of childhood tumours in Great Britain. METHODS: A case-control study of paternal occupational data for 2920 cases of neuroblastoma, born and diagnosed in Great Britain between 1962 and 1999 and recorded in the National Registry of Childhood Tumours, and 2920 controls from the general population matched on sex, date of birth and birth registration district. Paternal occupations at birth, of the case or control child, were grouped by inferred exposure using an occupational exposure classification scheme. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CI), for each of the 32 paternal occupational exposure groups. RESULTS: Only paternal occupational exposure to leather was statistically significantly associated with neuroblastoma, OR=5.00 (95% CI 1.07-46.93). However, this association became non-significant on correction for multiple testing. CONCLUSION: Our findings do not support the hypothesis that paternal occupational exposure is an important aetiological factor for neuroblastoma.

Surgical management and long-term outcome of dogs with cervical spondylomyelopathy with an anchored intervertebral titanium device.

OBJECTIVE: To assess the short- and long-term outcome of an anchored intervertebral titanium device (C-LOX) for the treatment of 10 dogs with disc-associated cervical spondylomyelopathy (DACSM) and 1 dog with osseous-associated cervical spondylomyelopathy. DESIGN: Retrospective case series. METHODS: Dogs were included if they were diagnosed with either DACSM or osseous-associated cervical spondylomyelopathy via myelography with or without advanced imaging and underwent surgical distraction and stabilisation of the affected intervertebral disc with a C-LOX implant. Assessment included short-term neurological outcome, radiography immediately and 6 weeks' postsurgery, owner questionnaire and veterinary clinical assessment. RESULTS: The mean follow-up time was 12 months. Improvement in neurological status was noted in 10 of 11 dogs. Screw loosening or subsidence occurred in five dogs. Revision surgery was performed in two dogs due to implant fracture (n = 1) and recurrence of spinal cord compression due to endplate subsidence around the implant (n = 1). Adjacent segment disease occurred in three dogs (30%) with DACSM at a mean of 11 months postsurgery. CONCLUSION: The use of the C-LOX implant for dogs with cervical spondylomyelopathy resulted in a high rate of initial neurological improvement; however, there is a moderate incidence of minor and major complications that is comparable to previously described distraction-stabilisation techniques.

Mitochondrial genetics cooperate with nuclear genetics to selectively alter immune cell development/trafficking.

The nuclear genome drives differences in immune cell populations and differentiation potentials, in part regulated by changes in metabolism. Despite this connection, the role of mitochondrial DNA (mtDNA) polymorphisms (SNP) in this process has not been examined. Using mitochondrial nuclear exchange (MNX) mice, we and others have shown that mtDNA strongly influences varying aspects of cell biology and disease. Based upon an established connection between mitochondria and immune cell polarization, we hypothesized that mtDNA SNP alter immune cell development, trafficking, and/or differentiation. Innate and adaptive immune cell populations were isolated and characterizated from the peritoneum and spleen. While most differences between mouse strains are regulated by nuclear DNA (nDNA), there are selective changes that are mediated by mtDNA differences (e.g., macrophage (CD11c) differentiation), These findings highlight how nuclear-mitochondrial crosstalk may alter pathology and physiology via regulation of specific components of the immune system.

Wilms tumour and paternal occupation: an analysis of data from the National Registry of Childhood Tumours.

BACKGROUND: Wilms tumour is an embryonal malignant tumour that accounts for 90% of childhood kidney cancers. Parental occupational exposure has been hypothesised to be a cause of childhood Wilms tumour, in particular exposure to pesticides. However, the findings are inconsistent. PROCEDURE: We have examined the association between paternal occupational exposures and Wilms tumour using birth registration data for cases (n = 2568) from the National Registry of Childhood Tumours (NRCT) and matched controls (n = 2,568) drawn from the general population of Great Britain. Paternal occupation, as recorded at the time of birth, was used to infer "occupational exposure" using a previously defined occupational exposure classification scheme. Odds ratios and 95% confidence intervals were generated using conditional logistic regression with exact methods to estimate the association between each paternal occupational exposure group and childhood Wilms tumour. RESULTS: All odds ratios were close to 1.00 and no statistically significant associations were observed. CONCLUSION: The results of this study failed to support any of the previously identified associations between paternal occupation and childhood Wilms tumour.

Paternal occupation and retinoblastoma: a case-control study based on data for Great Britain 1962-1999.

OBJECTIVES: To examine the association between paternal occupational exposures and retinoblastoma using birth registration data for cases from the National Registry of Childhood Tumours (NRCT) and controls from the general population of Great Britain. METHODS: A case-control study of paternal occupational data for 1318 cases of retinoblastoma, born and diagnosed in Great Britain between 1962 and 1999, and 1318 controls matched on sex, date of birth and birth registration sub-district. Paternal occupations at birth were grouped according to inferred exposure using an occupational exposure classification scheme. A conditional (matched) case-control analysis was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI) for each paternal occupational exposure group. RESULTS: For non-heritable retinoblastoma, a statistically significant increased risk was found with father's definite occupational exposure to oil mists in metal working (OR = 1.85 (95% CI 1.05 to 3.36)). Together with a (non-significant) risk (OR = 1.64 (0.73 to 3.83)) amongst the heritable cases, this occupational exposure was also associated with a significant increased risk when all retinoblastoma cases were considered together (OR = 1.77 (1.12 to 2.85)). No statistically significant associations were observed for other exposure groups. CONCLUSIONS: Our finding for exposure to oil mists in metal working (a subset of metal workers) is not directly comparable to those for metal working previously reported in the literature. Overall, our findings do not support the hypothesis that paternal occupational exposure is an important aetiological factor for retinoblastoma, however, the study has low power and other methodological limitations.

Pathways and mechanisms linking dietary components to cardiometabolic disease: thinking beyond calories.

Calories from any food have the potential to increase risk for obesity and cardiometabolic disease because all calories can directly contribute to positive energy balance and fat gain. However, various dietary components or patterns may promote obesity and cardiometabolic disease by additional mechanisms that are not mediated solely by caloric content. Researchers explored this topic at the 2017 CrossFit Foundation Academic Conference 'Diet and Cardiometabolic Health - Beyond Calories', and this paper summarizes the presentations and follow-up discussions. Regarding the health effects of dietary fat, sugar and non-nutritive sweeteners, it is concluded that food-specific saturated fatty acids and sugar-sweetened beverages promote cardiometabolic diseases by mechanisms that are additional to their contribution of calories to positive energy balance and that aspartame does not promote weight gain. The challenges involved in conducting and interpreting clinical nutritional research, which preclude more extensive conclusions, are detailed. Emerging research is presented exploring the possibility that responses to certain dietary components/patterns are influenced by the metabolic status, developmental period or genotype of the individual; by the responsiveness of brain regions associated with reward to food cues; or by the microbiome. More research regarding these potential 'beyond calories' mechanisms may lead to new strategies for attenuating the obesity crisis.

A proposed method for assessing plasma hypertonicity in vivo.

Indices of plasma hypertonicity, elevated plasma concentrations of solutes that draw fluid out of cells by osmosis, are needed to pursue hypertonicity as a possible risk factor for obesity and chronic disease. This paper proposes a new index that may be more sensitive to mild hypertonicity in vivo at a point in time than traditional measures. The index compares mean corpuscular volume (MCV) estimates from diluted (in solution by automated cell counter) and nondiluted blood (calculated from manual hematocrit, MCV=Hct/RBC*10(6)). A larger Auto vs Manual MCV (>2 fl) in vitro indicates hypertonicity in vivo if the cell counter diluent is isotonic with the threshold for plasma vasopressin (PVP) release and PVP is detectable in plasma (>0.5 pg/ml). To evaluate this principle of concept, hypertonicity was induced by 24-h fluid restriction after a 20 ml/kg water load in four healthy men (20-46 years). Unlike serum and urine indices, the MCV difference-&-PVP index detected hypertonicity in all participants.

Hyperzincuria in IDDM women. Relationship to measures of glycemic control, renal function, and tissue catabolism.

Eighteen women with insulin-dependent diabetes mellitus (IDDM) and 15 nondiabetic women participated in a study of the relationship of zincuria to measures of glycemic control, renal function, and tissue catabolism. In the IDDM women, mean +/- SE glycosylated hemoglobin was 9.8 +/- 0.5%, and fasting plasma glucose was 189 +/- 19 mg/dl; duration of diabetes averaged 15 yr. In comparison with control women, the IDDM women excreted four times as much zinc in the urine. However, the total plasma zinc concentration was significantly higher in the IDDM than in the control women (14.7 vs. 13.4 microM). The increased urinary zinc loss in the IDDM women was not related to urine volume, urinary glucose excretion, fasting plasma glucose concentration, percent glycosylated hemoglobin, or an increased glomerular filtration rate. Total urinary protein losses were four times higher in the IDDM women than in the control women, and these urinary protein losses correlated with the urinary zinc losses (P less than .007). There was no relationship between urinary zinc and the excretion of any of the amino acids, urea, or ammonia. The results of this study show that hyperzincuria in diabetes is not associated with lower plasma zinc levels. An increased zinc absorption, decreased intestinal zinc excretion, or increased tissue catabolism may support higher plasma zinc levels.

Luteinizing hormone-releasing hormone terminals in the median eminence of rats undergo dramatic changes after gonadectomy, as revealed by electron microscopic image analysis.

Despite intense investigation, the modulation of LHRH release, essential to reproduction, is not fully defined. In this study we investigated whether dynamic transformations of individual LHRH terminals in the median eminence of the hypothalamus occurred as a function of gonadectomy in rats, using immunocytochemistry and electron microscopy with quantitative image analysis. One day after castration, the distance between LHRH terminals and the basal lamina was reduced by 50% as LH levels rose significantly. By contrast, in females, this distance did not decrease until 6 days after ovariectomy, coincident with a delayed rise in LH levels. The percent area of each immunopositive terminal occupied by LHRH reaction product was smaller in intact males than females and increased after castration to reach a maximum 3 weeks after castration. By contrast, in females, the greatest percent area was observed in control diestrous females and decreased to a minimum 3 weeks after ovariectomy. Three weeks after gonadectomy, distance and area measurements no longer displayed significant sex differences. Transformations of LHRH terminals may be modulated by direct action on LHRH terminals or intervening neuronal or nonneuronal elements in the median eminence. Modulating factors may derive from local elements or circulating factors bound to local extracellular matrix.

The number and distribution of detectable luteinizing hormone (LH)-releasing hormone cell bodies changes in association with the preovulatory LH surge in the brains of young but not middle-aged female rats.

The population of LHRH neurons was examined in young and middle-aged female rats at two different time points associated with the LH surge on proestrus. More immunopositive LHRH neurons were detected in the brains of young but not middle-aged females killed on the evening of proestrus (1830-2030 h) compared with those killed earlier in the afternoon (1300-1430 h). To facilitate the investigation of potential regional differences within the population, sections through the basal forebrain were divided into four areas based upon their rostral-caudal position. Whereas no change in detectability was observed in the most rostral subset of LHRH neurons, more LHRH perikarya were observed at the later compared to the earlier time point in the other three areas surveyed in the brains of young females. Only the increase observed in sections through the preoptic area, however, reached statistical significance. Computer assisted three-dimensional reconstruction of all LHRH neurons in sections through the preoptic area revealed a marked increase in a subgroup of LHRH neurons in the dorsomedial aspect of this region of the population. Changes in detectability of LHRH neurons in association with the LH surge suggest that these neurons may be involved in regulating preovulatory LH release. Examination of additional time points could reveal changes in other subgroups of LHRH neurons as well as significant changes in detectability of LHRH neurons in aging brains.

Reconstructions of populations of luteinizing hormone releasing hormone neurons in young and middle-aged rats reveal progressive increases in subgroups expressing Fos protein on proestrus and age-related deficits.

Fos expression has been used as a marker of activation of neuroendocrine cells including LHRH neurons. In this study, Fos protein was localized within LHRH neurons in young and middle-aged rats to trace the temporal and spatial pattern of LHRH neuronal activation associated with the preovulatory LH surge. Animals were killed during the late morning, afternoon, and evening of proestrus. Dual immunocytochemical protocols localized LHRH and LHRH/Fos neurons, and computer-assisted methods were used to reconstruct forebrain populations of single- and double-labeled LHRH neurons. Although a significant increase in the number of LHRH/Fos neurons was noted by evening in both age groups, a greater increase was observed in young (12% in morning, 28% in afternoon, and 62% by evening) compared with aging females (5% in morning, 10% in afternoon, and 40% by evening). Reconstructions of LHRH and LHRH/Fos neurons revealed time- and age-dependent differences in Fos expression within LHRH neurons. In young females, LHRH/Fos neurons were restricted to central regions of the population of LHRH neurons on the morning of proestrus. By evening, Fos expression was also observed in more peripheral and caudal LHRH neurons. In middle-aged females, Fos expression was restricted to ventral subgroups of LHRH neurons on the afternoon of proestrus. By evening, more LHRH neurons contained Fos protein, however, few were located in the dorsal aspect of the population. These data trace the progressive increase in activation of LHRH neurons during the preovulatory LH surge in young females and reveal deficits in this pattern of activation by middle age.

Examination of guinea pig luteinizing hormone-releasing hormone gene reveals a unique decapeptide and existence of two transcripts in the brain.

We sequenced the complementary DNA (cDNA) encoding guinea pig LHRH from an expression library derived from the preoptic area-anterior hypothalamus. Data from in situ hybridization and RNase protection assays verified that the cloned cDNA was complementary to guinea pig LHRH messenger RNA. The architecture of the deduced precursor resembles that of LHRH precursors identified in other species. In contrast, the predicted sequence of the decapeptide differs from mammalian LHRH by two amino acid substitutions in positions 2 and 7. This is a novel finding, because the amino acid sequence that comprises LHRH decapeptide is identical in all mammals studied to date. Moreover, the predicted substitution in amino acid position 2 is unique among vertebrates. A second observation of potential significance is the existence of two subspecies of LHRH messenger RNA differing only in the length of their 3' untranslated regions. These two transcripts were verified by sequence analysis of positive clones from the cDNA library and by RNase protection analysis of preoptic area-anterior hypothalamus extracts, and their presence is consistent with the two polyadenylation signals identified in the untranslated regions of the LHRH gene. Future studies will examine LHRH gene expression in guinea pigs, which like primates but unlike rats, have a true luteal phase as a component of their reproductive cycle.

Processing of luteinizing hormone-releasing hormone precursor in rat neurons.

Results of previous immunocytochemical studies indicate that in the rat brain proteolytic cleaving of LHRH precursors to generate the physiologically active decapeptide takes place within neuronal fibers and terminals and not within perikarya. A 69-amino acid (aa) LHRH precursor comprised of the decapeptide, a 3-aa cleavage and amidation site, and a 56-aa C-terminal extension has recently been characterized. Two antisera generated to specific aa sequences of the C-terminal extension (RM 8/5, anti aa 14-26; PS 39A, anti aa 40-53) and two directed to specific regions of the LHRH decapeptide (RM 1076, anti aa 4-8; A 422 generated to the N-terminal pGlu and C-terminal amidated Gly) were used to further examine intraneuronal sites of precursor processing. Patterns of immunoreactivity revealed with antisera directed to non-LHRH sequences of LHRH precursor paralleled those observed with antisera to the decapeptide. Immunopositive perikarya, processes, and neurovascular terminals were observed with PS 39A. Antiserum PS 39A binds to an internal aa sequence of the C-terminal extension and would, therefore, be expected to detect intact precursor LHRH as well as products of proteolytic cleavage. In contrast, only immunopositive processes and neurovascular terminals were observed with RM 8/5, an antiserum directed to an initial aa sequence of the C-terminal extension. The pattern of immunoreactivity revealed with RM 8/5 resembled that observed with an antiserum that binds the fully processed decapeptide (A 422), indicating that proteolytic cleavage of the decapeptide from the C-terminal extension is required for binding by this antiserum. Furthermore, the restricted distribution of reaction product observed with RM 8/5 relative to A 422 suggests that additional processing of the C-terminal extension may be required for binding. Such additional processing appears to occur in neurovascular terminals of the median eminence.

Expression of gamma-aminobutyric acid and gonadotropin-releasing hormone during neuronal migration through the olfactory system.

Neurons containing the decapeptide GnRH originate in the olfactory placodes and migrate into the central nervous system during fetal development. The neurotransmitter gamma-aminobutyric acid (GABA) has been proposed as a trophic factor and may also influence neuronal migration. Immunocytochemical analyses were conducted in fetal rats, mice, and humans to identify potential developmental relationships between cells containing GABA, and GnRH neurons. Cells containing GABA were found along the nasal portion of the GnRH migration pathway in rats, mice, and humans during development. A peak number of cells containing immunoreactive GABA was observed in the nasal compartment of rats at embryonic day 15. At this time (E15), a majority of GnRH neurons were clustered in the region of the cribriform plate. By postnatal day 1, all GnRH neurons had migrated into the CNS and GABA cells were virtually absent from the nasal compartment. Double-label and confocal analyses of GABA and GnRH in mice and rats demonstrated that some olfactory GABAergic neurons coexpress GnRH. This implies that neurons that transiently express GABA originate in olfactory placodes and migrate into the forebrain. Based on the transient dual-label and adjacent relationships between GABA and GnRH containing cells in the nasal compartment, and other data showing migrational and trophic roles for GABA in development, we suggest that GABA may directly influence GnRH neuronal migration and development.

Computer-assisted mapping of immunoreactive mammalian gonadotropin-releasing hormone in adult human basal forebrain and amygdala.

Immunocytochemistry performed on 80-microns unembedded tissue sections was used to study the localization of GnRH-containing neurons and fibers in the basal forebrain and amygdala of six adult (four male, two female) human brains. Sections from one of the female brains were subjected to computer-assisted microscopic mapping to generate a three-dimensional analysis of immunoreactive structures. In all six brains examined, cell bodies were concentrated in the preoptic area and basal hypothalamus, but were also evident in the septal region, anterior olfactory area, and cortical and medial amygdaloid nuclei. GnRH-containing fibers were observed within the hypothalamus (predominantly infundibular region and preoptic area), septum, stria terminalis, ventral pallidum, dorsomedial thalamus, olfactory stria, and anterior olfactory area. Many fibers could also be seen coursing along the base of the brain between the hypothalamus and cortical and medial amygdaloid nuclei. The localization of GnRH-containing cells and fibers in several of these areas represents new observations in the human brain and suggests a role for the amygdaloid complex in the regulation of gonadotropin secretion. The comprehensive view provided by these data may be useful in the clinical application of novel transplantation strategies.

Subgroups of luteinizing hormone-releasing hormone perikarya defined by computer analyses in the basal forebrain of intact female rats.

The hypothesis that the basal forebrain population of LHRH perikarya is composed of heterogeneous subgroups was examined in this study. We used three-dimensional computerized reconstruction to examine populations of LHRH-immunopositive neurons detected in noncolchicine treated cycling female rats. Perikarya were detected with two antisera capable of detecting LHRH decapeptide within larger mol wt species, i.e. Millar's (RM) 1076 and Arimura's (AA) 419. No immunopositive perikarya were detected with antiserum AA 422, which requires the fully processed decapeptide for binding. A more broadly distributed population of LHRH neurons was detected in females killed on proestrus than in females killed on estrus or the other days of the cycle. These relationships were observed with both antisera, RM 1076 and AA 419. Subgroups of cells were clearly defined when the population of LHRH neurons detected on proestrus was simultaneously displayed with the population detected on estrus. Strikingly similar subgroups were revealed by simultaneous displays of populations of LHRH neurons detected by the antisera RM 1076 and AA 419 in proestrous females. This study revealed a three-dimensional onion skin-like laminar organization of LHRH subgroups expanding from the ventricle outward laterally and from the diagonal band of Broca to the hypothalamus caudally. We propose that these subgroups vary in their metabolic activity of biosynthesis, processing, transport, or release of LHRH in relation to the proestrous preovulatory release of LH.

Luteinizing hormone-releasing hormone neurons in human preoptic/hypothalamus: differential intraneuronal localization of immunoreactive forms.

Luteinizing hormone-releasing hormone (LRH) may be synthesized as part of a larger prohormone, as are several other neuropeptides. In this study, we sought not only to define the distribution and morphological characteristics of LRH neurons within the human preoptic area and hypothalamus, but also to identify sites of initial synthesis, posttranslational conversion to the decapeptide, and storage of LRH in these neurons. Immunoreactive molecular forms were differentiated using a series of antisera with distinct specificities in the peroxidase-antiperoxidase technique. These antisera were capable of detecting the fully processed hormone as well as extended decapeptide sequences. Immunopositive LRH neurons were more abundant in the infundibular area of the hypothalamus than in the preoptic area. Numbers of immunopositive perikarya and subcellular distribution of reaction product varied with binding requirements of the antisera. After treatment with an antiserum that requires the fully processed decapeptide for binding, the reaction product was associated almost entirely with granules in perikarya and processes, while very little was associated with either rough endoplasmic reticulum (RER) or Golgi apparatus. In contrast, with an antiserum capable of detecting extended forms of the decapeptide, the RER and Golgi were labeled in addition to granules. From these data, we infer that in humans, mature decapeptide is present in granules within LRH neuronal perikarya and processes. Furthermore, the molecular forms associated with RER and Golgi may be precursors in which the decapeptide sequence is extended.