Physicochemical determinants of pH in pectoralis major of three strains of laying hens housed in conventional and furnished cages.

1. Post-mortem decline in muscle pH has traditionally been attributed to glycogenolysis-induced lactate accumulation. However, muscle pH ([H+]) is controlled by complex physicochemical relationships encapsulated in the Stewart model of acid-base chemistry and is determined by three system-independent variables - strong ion difference ([SID]), total concentration of weak acids ([Atot]) and partial pressure of CO2 (PCO2). 2. This study investigated these system-independent variables in post-mortem pectoralis major muscles of Shaver White, Lohmann Lite and Lohmann Brown laying hens housed in conventional cages (CC) or furnished cages (FC) and evaluated the model by comparing calculated [H+] with previously measured [H+] values. 3. The model accounted for 99.7% of the variation in muscle [H+]. Differences in [SID] accounted for most or all of the variations in [H+] between strains. Greater PCO2 in FC was counteracted by greater sequestration of strong base cations. The results demonstrate the accuracy and utility of the Stewart model for investigating determinants of meat [H+]. 4. The housing differences identified in this study suggested that hens housed in FC have improved muscle function and overall health due to the increased opportunity for movement. These findings support past studies showing improved animal welfare for hens housed in FC compared to CC. Therefore, the Stewart model has been identified as an accurate method to assess changes in the muscle at a cellular level that affect meat quality that also detect differences in the welfare status of the research subjects.

Herpes simplex virus type 2 antibody detection performance in Kisumu, Kenya, using the Herpeselect ELISA, Kalon ELISA, Western blot and inhibition testing.

BACKGROUND: In certain parts of Africa, type-specific herpes simplex virus type 2 (HSV-2) ELISAs may have limited specificity. To date, no study has been conducted to validate HerpeSelect and Kalon type-specific HSV-2 ELISAs using both the Western blot and recombinant gG ELISA inhibition testing as reference standards. METHODS: A total of 120 men who were HIV seronegative (aged 18-24 years) provided blood samples. HSV-2 IgG serum antibodies were detected using four different methods: HerpeSelect HSV-2 ELISA (n = 120), Kalon HSV-2 ELISA (n = 120), University of Washington Western blot (n = 101) and a recombinant inhibition test (n = 93). RESULTS: HSV-2 seroprevalence differed significantly by HSV-2 detection method, ranging from 24.8% with the Western blot to 69.8% with the HerpeSelect ELISA. Using the Western blot as the reference standard, the HerpesSelect had the highest sensitivity for HSV-2 antibody detection (100%) yet lowest specificity (40%). Similar results were obtained using the inhibition test as the reference standard. The sensitivity and specificity of the Kalon test versus the Western blot were 92% and 79%, respectively, and 80% and 82% versus the inhibition test. Using the inhibition test as the reference standard, the sensitivity of the Western blot appeared low (49%). CONCLUSIONS: In men in western Kenya who were HIV seronegative, the HerpeSelect and Kalon type-specific ELISAs had high sensitivities yet limited specificities using the Western blot as reference standard. Overall, the Kalon ELISA performed better than the HerpeSelect ELISA in these young men from Kisumu. Further understanding is needed for the interpretation of HSV-2 inhibition or ELISA test positive/ Western blot seronegative results. Before HSV-2 seropositivity may be reliably reported in selected areas of Africa, performance studies of HSV-2 serological assays in individual geographical areas are recommended.

Chlamydia trachomatis from individuals in a sexually transmitted disease core group exhibit frequent sequence variation in the major outer membrane protein (omp1) gene.

60 cervical Chlamydia trachomatis infections identified by antigen detection from 51 prostitute women in Nairobi, Kenya were evaluated for sequence polymorphism in the major outer membrane protein (omp1) gene. DNA from clinical specimens was amplified by the polymerase chain reaction and cycle sequenced through variable domains (VD) 1, 2, and 4.37 (63%) samples had variant VD sequences, 19 (32%) samples had prototype VD sequences, and 4 (6%) samples had prototype VD sequences, and 4 (6%) samples contained omp1 sequences from two or more C. trachomatis strains. Among the 37 variant strains, 18 had two or fewer nucleotide substitutions in one or two VDs and represented point mutational drift variants. 19 strains had a larger number of nucleotide changes and displayed mosaic omp1 sequences that may have been generated by omp1 VD recombination. We conclude that the prevalence of C. trachomatis omp1 DNA polymorphism is substantial among prostitute women in Nairobi, Kenya and that this is the likely result of immune selection pressure.

Antibody to Rmp (outer membrane protein 3) increases susceptibility to gonococcal infection.

The severe adverse effects of gonococcal infection on human fertility suggests that Neisseria gonorrhoeae would exert powerful selection for the development of a protective immune response in humans. N. gonorrhoeae is an obligate human pathogen and must persist in humans to survive. Since it is an ecologically successful organism, it must have evolved strategies to evade any human immune response it elicits. In a longitudinal study among 243 women working as prostitutes and experiencing frequent gonococcal infection, younger women, women with HIV infection, and women with antibody to the gonococcal outer membrane protein 3 (Rmp) were at increased risk of infection (adjusted odds ratio 3.4, CI95% 1.1-10.4, P < 0.05). Rmp is highly conserved in N. gonorrhoeae and the blocking of mucosal defences may be one of its functions. As similar proteins occur in many gram negative mucosal pathogens, the enhancing effect of such proteins may be a general strategy whereby bacteria evade human immune responses.

PIP: Between March 1985 and July 1986 researchers enrolled 243 female prostitutes in Pumwani community of Nairobi, Kenya, in a longitudinal study to examine the relationship between the antibody to the gonococcal outer membrane protein 3 (Rmp Ab) and gonococcal mucosal infection. Few women used condoms. 69% were HIV-1 seropositive. Just 9.5% (23) of the women had not had any gonococcal infections, despite probable exposure to them, indicating the possibility of some acquired protective immunity to Neisseria gonorrhoea. 90.5% had had at least 1 gonococcal infection. Women with Rmp Ab faced a greater risk of gonococcal infection than those who were Rmp Ab negative (OR = 3.4;l p .05), denoting that Rmp Ab increases susceptibility to gonococcal mucosal infections. Women older than 29 years were at lower risk of gonococcal infection than those younger than 29 years (odds ratio [OR] = 0.3; p .03). Women who used oral contraceptives (OCs) were also likely to be infected with N. gonorrhoea (OR = 3; p = .062). Further, 31% of OC users had cervical ectopy compared to just 14% of nonusers (OR = 2.8; p .005), suggesting that the effect of OCs on the cervix make it more susceptible to gonococcal infection. Rmp Ab also exists in many other gram-negative mucosal pathogens, often playing the same role as it does in N. gonorrhoea infection. Thus, Rmp Ab may be a common scheme bacteria used to elude human immune responses. These findings provide more understanding as to why N. gonorrhoea is an ecologically successful human pathogen.

Antibodies to opacity proteins (Opa) correlate with a reduced risk of gonococcal salpingitis.

Acute salpingitis complicating cervical gonococcal infection is a significant cause of infertility. Relatively little data are available concerning the pathophysiologic mechanisms of this disease. A cohort of 243 prostitutes residing in Nairobi were followed between March 1985 and April 1988. Gonococcal cultures were performed at each visit, and acute salpingitis was diagnosed clinically. Serum at enrollment was tested by immunoblot for antibody to gonococcal outer membrane proteins. 8.6% (146/1689) of gonococcal infections were complicated by salpingitis. Increased risk of salpingitis was associated with younger age, shorter duration of prostitution, HIV infection, number of gonococcal infections, and episodes of nongonococcal salpingitis. Rmp antibody increased the risk of salpingitis. Antibody to Opa decreased the risk of salpingitis. By logistic regression analysis, antibody to Opa was independently associated with decreased risk of gonococcal salpingitis (adjusted odds ratio [OR], 0.35; 95% confidence interval [95%CI], 0.17-0.76); HIV infection (adjusted OR, 3.5; 95% CI, 0.96-12.8) and episodes of nongonococcal salpingitis (adjusted OR, 3.4; 95% CI, 1.8-6.4) were independently associated with an increased risk of salpingitis. Antibody to Opa appears to protect against ascending gonococcal infection, perhaps by interfering with Opa mediated adherence and endocytosis. The demonstration of natural immunity that protects against upper genital tract infection in women suggests that a vaccine to prevent gonococcal salpingitis is possible.

Increased interleukin-10 in the the endocervical secretions of women with non-ulcerative sexually transmitted diseases: a mechanism for enhanced HIV-1 transmission?

OBJECTIVE: Although non-ulcerative sexually transmitted diseases (STD) and bacterial vaginosis are implicated as cofactors in heterosexual HIV-1 transmission, the mechanisms have not been defined. Recent in vitro data suggest that interleukin (IL)-10 may increase susceptibility of macrophages to HIV-1 infection. Therefore, we performed this study to assess whether non-ulcerative STD are associated with detection of IL-10 in the female genital tract. METHODS: Women with clinical pelvic inflammatory disease with or without cervicovaginal discharge were recruited from an STD clinic in Nairobi, Kenya. Endocervical and endometrial specimens were obtained for Neisseria gonorrhoeae and Chlamydia trachomatis DNA detection, Trichonomas vaginalis culture, and CD4 and CD8 T-cell enumeration. Bacterial vaginosis was diagnosed by Gram stain. IL-10 was detected in endocervical specimens using enzyme-linked immunosorbent assay. Blood was obtained for HIV-1 serology. RESULTS: One hundred and seventy-two women were studied. N. gonorrhoeae, C. trachomatis, bacterial vaginosis, and T. vaginalis were detected in 38 (21%), 17 (9%), 71 (43%), and 22 (12%) women, respectively. Cervical IL-10 was detected more often in women with N. gonorrhoeae [adjusted odds ratio (AOR), 3.4; 95% confidence interval (CI), 1.4-8.4], C. trachomatis (AOR, 4.4; 95% CI, 1.2-15.6), and bacterial vaginosis (AOR, 3.1; 95% CI, 1.4-6.9) than in women without these infections. CONCLUSIONS: The association of non-ulcerative STD and bacterial vaginosis with increased frequency of IL-10 detection in endocervical secretions suggests a potential mechanism through which these infections may alter susceptibility to HIV-1 infection in women.

Functional electrical stimulation exercise increases GLUT-1 and GLUT-4 in paralyzed skeletal muscle.

The study purpose was to determine the effect of functional electrical stimulation (FES)-leg cycle ergometer training (30 minutes on 3 d/wk for 8 weeks) on the GLUT-1 and GLUT-4 content of paralyzed skeletal muscle. Biopsy samples of vastus lateralis muscle were obtained pre- and post-training from five individuals with motor-complete spinal cord injury ([SCI] four men and one woman aged 31 to 50 years, 3 to 25 years postinjury involving C5-T8). Western blot analysis indicated that GLUT-1 increased by 52% and GLUT-4 increased by 72% with training (P < .05). This coincided with an increase in the muscle oxidative capacity as indicated by a 56% increase in citrate synthase (CS) activity (P < .05) and an improvement in the insulin sensitivity index as determined from oral glucose tolerance tests (P < .05). It is concluded that FES endurance training is effective to increase glucose transporter protein levels in paralyzed skeletal muscle of individuals with SCI.

Cationized ferritin and phosvitin uptake by coated vesicles of the early chick embryo.

The endocytosis of cationized ferritin and of a phosvitinferritin conjugate by cells of the chick embryo area pellucida has been examined. Cationized ferritin was bound mainly to the free surface of the epiblast but was absent from the region of the primitive streak. The binding was patchy and experiments suggest that the anionic sites which bind cationized ferritin are themselves naturally clustered. Uptake of cationized ferritin was exclusively by coated pits. The resulting coated vesicles delivered the cationized ferritin to membrane-bound sites of accumulation in the cytoplasm and to the close vicinity of Golgi bodies. The cationized ferritin was frequently found to share intracellular vacuoles with yolk granules. The uptake was not affected by the presence of microfilament or microtubule-inhibiting agents. Native ferritin, even at concentrations forty times that of cationized ferritin, was not bound or endocytosed. Coated pits in the epiblast were often associated with overlying extracellular yolk granules. This suggested that the yolk might be inducing the formation of the coated pits. The yolk protein phosvitin was coupled to ferritin and this conjugate was found to be endocytosed by coated pits. This uptake was inhibited in the presence of an excess of free phosvitin but not by albumin, indicating some selectivity for phosvitin over other proteins. The phosvitin conjugate was also found sharing intracellular vacuoles with yolk. We conclude that the cells of the area pellucida, and in particular those of the epiblast, have an active coated vesicle uptake system which may be able to selectively endocytose yolk or yolk protein.

Genotyping of Neisseria gonorrhoeae by Pulse Field Gel Electrophoresis and PCR.

Auxotyping (growth of cells on chemically defined media) and serotyping (reaction of cells with a defined set of monoclonal antibodies [MAbs]) are the traditional and most widely used methods for the classification of Neisseria gonorrhoeae isolates. As an example, Knapp et al. (1) used the combination of these two typing techniques to study the epidemiology of 489 isolates of N. gonorrhoeae collected over a 3-mo time period. Separately, 11 different auxotypes and 19 different serotypes were found, but when combined, a total of 57 auxotype/serotype classes were identified. Although this system was and still is very useful for epidemiological studies, some laboratories felt more comfortable using molecular techniques to classify their gonococcal isolates.

Effects of 10-ppm hydrogen sulfide inhalation in exercising men and women. Cardiovascular, metabolic, and biochemical responses.

This study examined the acute effects of 10-ppm hydrogen sulfide (H2S) inhalation, a concentration equal to its occupational exposure limit, on the cardiovascular, metabolic, and biochemical responses in healthy volunteers. Fifteen men and 13 women completed two 30-minute exercise sessions at 50% of their maximal oxygen uptake, during which they inhaled medical air or 10 ppm H2S in a blind manner. Arterial and finger-prick blood samples were obtained before and during the final minute of exercise. Muscle biopsies were withdrawn from the right vastus lateralis immediately after exercise. Cardiorespiratory measurements were monitored using an automated metabolic cart interfaced with an electrocardiogram and blood pressure apparatus. A significant decrease in oxygen uptake (VO2), with a concomitant increase in blood lactate, was observed in men and women as a result of H2S exposure. No significant changes were observed in arterial blood parameters and the cardiovascular responses under these conditions. Muscle lactate, as well as the activities of lactate dehydrogenase, citrate synthase, and cytochrome oxidase, were not significantly altered by H2S exposure. However, there was a tendency for muscle lactate to increase and citrate synthase activity to decrease in both genders in the presence of H2S. It appeared that 10-ppm H2S inhalation reduced VO2 during exercise, most likely by inhibiting the aerobic capacity of the exercising muscle. These findings question the scientific validity of the current occupational exposure limit for H2S.

Effects of 10-ppm hydrogen sulfide inhalation on pulmonary function in healthy men and women.

This study examined the acute effects of oral inhalation of 10-ppm hydrogen sulfide (H2S) inhalation (a concentration equal to its occupational exposure limit) on the pulmonary function in healthy men and women. Nine men and ten women consented to inhale medical air or 10 ppm H2S for 15 minutes each during cycle exercise at 50% of their maximal aerobic power. Routine pulmonary function tests were administered at rest and immediately after the two exposure conditions. The results indicated no significant changes in any of the variables derived from the flow volume loop, maximum ventilation volume, and diffusion capacity of the lung for carbon monoxide in both genders. None of the subjects experienced any signs and symptoms as a result of H2S exposure. It was concluded that oral inhalation of 10 ppm H2S at an elevated metabolic and ventilation rate does not significantly alter pulmonary function in healthy men and women.

Plasma and extracellular volume in calves: comparison between isotopic and 'cold' techniques.

While isotopic techniques have largely superseded traditional markers for the determination of the volume of fluid compartments in vivo, they are not always convenient, especially with diarrhoeic animals. A direct comparison was therefore made in week-old calves between Evans blue and radio-iodinated serum albumin as measures of plasma volume and thiocyanate or 24sodium as measures of extracellular fluid space. The correlation coefficients were excellent (1.00, 0.96; P < 0.001) and the calves had plasma and extracellular fluid volumes of 72 +/- 2 and 438 +/- 2 ml kg-1, respectively. The latter value is, though high, typical of young animals and comparable with other data in calves.

Pharmaceutical management in ProCare Health Limited.

AIMS: To review pharmaceutical budget holding and management in ProCare Health Limited by; describing budget holding strategies implemented in 1995/6, identifying prescribing savings achieved, analysing variation in prescribing behaviour and comparing the findings with experience elsewhere. METHODS: With 340 members, ProCare is one of the largest and most progressive of New Zealand's independent practitioner associations (IPAs). Data were obtained for the three years 1994 to 1996 to determine pharmaceutical expenditure against budget and against national trends, by member and general medical services (GMS) consultations. RESULTS: ProCare has established a classical, quality focussed pharmaceutical management strategy. Savings against the agreed budget was 9.5% comparing 1996 with 1995 but 5.7% compared, with national trends. Wide variation in per capita and per consultation costs was not reduced and was entirely explained by prescribing volumes not drug prices. CONCLUSIONS: The most important finding is that general practitioners (GPs), working collaboratively, can establish a strategy of clinical and corporate governance which may be exerting a wide ranging influence over clinical behaviour. Although there may be doubts about the actual levels of saving these appeared to be well in excess of the financial investment in the strategy. Greater savings appear possible with a focus on addressing the large and apparently inappropriate per capita prescribing volume variation between practices. Understanding and successfully addressing this variation will be one of the key issues facing the implementation of the government's primary health care strategy.

Effect of high velocity resistance training on peak torque, cross sectional area and myofibrillar ATPase activity.

The purpose of this investigation was to determine the effect of high velocity resistance (HVR) training on peak torque (PT), cross sectional area (CSA) and myofibrillar ATPase activity of the knee extensors. HVR training was performed in a circuit on hydraulic exercise equipment, 4 times a week for 5 weeks at an angular velocity of approximately 3.14 rad.s-1. Knee extension PT was determined on a Cybex II isokinetic dynamometer and CSA of the quadriceps femoris muscle was assessed using computer tomography (CT) scanning. Muscle biopsies were obtained from the lateral quadriceps muscle and were analyzed for myofibrillar ATPase activity. Knee extension peak torque was significantly increased at 1.57, 2.09, 3.14, 3.66 and 4.19 rad.s-1. Myofibrillar ATPase activity and CSA was also significantly increased after HVR training. These findings showed that short-term high velocity resistance training enhances the in vivo torque/velocity curve especially at fast angular velocities and these changes are partly attributed to an increase in muscle CSA and activity of myofibrillar ATPase.

Low dose erythromycin regimen for the treatment of chancroid.

Haemophilus ducreyi is the commonest cause of genital ulcer disease in Africa and is associated with heterosexual transmission of human immunodeficiency virus(HIV). The World Health Organization currently recommends erythromycin 500 mg three times a day for seven days as the treatment of choice for Haemophilus ducreyi infection. We studied the effectiveness of a lower dose erythromycin treatment regime, 250 mg three times a day for seven days in the treatment of chancroid. Patients with genital ulcer disease presenting at Nairobi City council clinic between January and March, 1992 were recruited into the study. Swabs were taken from the ulcers for Haemophilus ducreyi and venous blood was screened for syphilis and HIV antibodies. A total of 219 patients were enrolled for the study and were reviewed on days seven and fourteen for side effects, bacteriological and clinical cure rates. 26.4% of the study population were HIV-1 seropositive. The treatment regime was well tolerated and effective in both HIV seropositive and seronegative patients. Complete bacteriological cure rate was achieved in Haemophilus ducreyi culture positives by day seven irrespective of the HIV serostatus. However, the clinical cure rate for HIV seropositive patients was 88% compared to 99% for seronegative patients (p<.001). It is concluded that a low dose erythromycin is an inexpensive and effective treatment for chancroid with complete bacteriological cure rate, although the healing process takes longer in HIV seropositive patients.

Stimulating conversations in needle EMG.

Needle electromyography (EMG) is a widely used modality that has been available for decades. Yet never has this invasive mode of EMG been enveloped in greater controversy than it is today. To explain the status--and future--of needle EMG while casting light upon the controversies surrounding it, Rehab Management spoke with three noted specialists in the field.