Group B Streptococcus Infections Caused by Improper Sourcing and Handling of Fish for Raw Consumption, Singapore, 2015-2016.

We assessed microbial safety and quality of raw fish sold in Singapore during 2015-2016 to complement epidemiologic findings for an outbreak of infection with group B Streptococcus serotype III sequence type (ST) 283 associated with raw fish consumption. Fish-associated group B Streptococcus ST283 strains included strains nearly identical (0-2 single-nucleotide polymorphisms) with the human outbreak strain, as well as strains in another distinct ST283 clade (57-71 single-nucleotide polymorphisms). Our investigations highlight the risk for contamination of freshwater fish (which are handled and distributed separately from saltwater fish sold as sashimi) and the need for improved hygienic handling of all fish for raw consumption. These results have led to updated policy and guidelines regarding the sale of ready-to-eat raw fish dishes in Singapore.

Factors influencing the acceptability of COVID-19 vaccination: A cross-sectional study from Malaysia.

Background: With the surge of COVID-19 cases worldwide, vaccines against COVID-19 are also developing across the countries. However, the acceptability of COVID-19 vaccination among general people is questionable. The availability of several vaccines' options against COVID-19 has perplexed people regarding individual vaccines' efficacy and safety. Therefore, we aim to determine the acceptance, preferences, impact factors of future COVID-19 vaccines in Malaysia and the factors influencing the COVID-19 vaccination acceptance among vaccine demand and vaccine delay groups. Material and methods: An online-based cross-sectional survey was conducted among Malaysian residents 18 years and above of either gender using the snowball sampling technique. A self-administered questionnaire was made available to participants through various social media networks, email, and telegram. The data obtained from the survey were analyzed using SPSS version 25.0. Association between background characteristics and respondents were analyzed using the Chi-square test in the vaccine delay group and vaccine acceptance group. Results: Total of 1282 responses were considered for the study, mainly from male respondents (71%). Among the respondents, 95.9% thought that vaccination would be an effective way to prevent and control COVID-19, and 96% would accept vaccination if the COVID-19 vaccine were successfully developed and approved for listing in the future. Essential factors influencing vaccination decisions were vaccine convenience (95.7%) and doctor's recommendation (97.3%). Bivariate analysis revealed that age less than 24 years, Malay race, living in urban areas, tertiary education, students, single marital status, family income (Malaysian ringgits) RM 4,850 to RM 10,959 and >RM 10,960 were significantly associated with vaccine acceptance of COVID19 vaccination. Conclusion: All the factors influencing COVID-19 vaccine acceptance rates throughout the country should be studied on a larger scale, and appropriate steps to ensure vaccine acceptance among the public should be meticulously devised by the government and related authorities.

Antecedentes: Con el aumento de casos de COVID-19 en todo el mundo, las vacunas contra la COVID-19 también están en desarrollo en todos los países. Sin embargo, la aceptabilidad de la vacuna COVID-19 entre la gente en general es cuestionable. La disponibilidad de varias opciones de vacunas contra COVID-19 ha dejado perpleja a la gente con respecto a la eficacia y seguridad de las vacunas individuales. Por lo tanto, tenemos como objetivo determinar la aceptación, las preferencias y los factores de impacto de las futuras vacunas COVID-19 en Malasia y los factores que influyen en la aceptación de la vacunación COVID-19 entre la demanda de vacunas y los grupos de demora de la vacuna. Material y métodos: Se realizó una encuesta transversal en línea entre residentes de Malasia de 18 años o más de cualquier género utilizando la técnica de muestreo de bola de nieve. Se puso a disposición de los participantes un cuestionario autoadministrado a través de varias redes sociales, correo electrónico y telegrama. Los datos obtenidos de la encuesta se analizaron con el programa SPSS versión 25.0. La asociación entre las características de fondo y los encuestados fueron analizados usando la prueba de χ2 en el grupo de demora de la vacuna y el grupo de aceptación de la vacuna. Resultados: Se consideró un total de 1.282 respuestas para el estudio, principalmente de hombres encuestados (71%). Entre los encuestados, el 95,9% pensó que la vacunación sería una forma eficaz de prevenir y controlar la COVID-19, y el 96% aceptaría la vacunación si la vacuna COVID-19 se desarrollara con éxito y se aprobara para su inclusión en el futuro. Factores esenciales que influyeron en las decisiones de vacunación fueron la conveniencia de la vacuna (95,7%) y la recomendación del médico (97,3%). El análisis bivariado reveló que la edad < 24 años, la raza malaya, la vida en áreas urbanas, educación terciaria, estudiantes, estado civil soltero, ingresos familiares RM 4,850 a RM 10,959 y > RM 10,960 (en ringgits, moneda malaya), se asociaron significativamente con la aceptación de la vacuna COVID-19. Conclusión: Todos los factores que influyen en las tasas de aceptación de la vacuna COVID-19 en todo el país deben estudiarse a mayor escala, y el gobierno y las autoridades relacionadas deben diseñar meticulosamente los pasos apropiados para asegurar la aceptación de la vacuna entre el público.

An international review and meta-analysis of prehabilitation compared to usual care for cancer patients.

PURPOSE: The purpose of the study is to systematically review and synthesise randomised controlled trials investigating the effectiveness of prehabilitation compared to usual care for newly diagnosed, adult-onset cancer patients. METHODS: MEDLINE, EMBASE, PsycINFO, CINAHL and SSCI were searched up to April 2017. Studies were included if disease-related, treatment-related, patient-reported and health service utilisation outcomes were assessed. Two reviewers independently reviewed and appraised the risk of bias of each study. RESULTS: Eighteen studies were included. Interventions comprised one or more of the following components: psychological support, education and exercise. Meta-analyses found that pelvic floor muscle training (PFMT) significantly increased odds of continence at 3 months (OR = 3.29, 95% CI = 1.57-6.91), but did not significantly reduce daily pad use at 6 months post-surgery Mean Difference (MD)= ( = - 0.96, 95% CI = - 2.04-0.12) for prostate cancer patients. Although quality of life improved due to PFMT, functional ability or distress did not. Further meta-analyses indicated that pre-surgical exercise significantly reduced length of hospital stay (MD = - 4.18, 95% CI = - 5.43-- 2.93) and significantly lowered odds of post-surgery complications (OR = 0.25, 95% CI = 0.10-0.66) for lung cancer patients. Psychology-based prehabilitation significantly improved mood, physical well-being and immune function for prostate cancer patients and improved fatigue and psychological outcomes and a trend for better quality of life among breast cancer patients. Risk of bias was high for most studies. CONCLUSIONS: Prehabilitation appears to benefit cancer patients. Rigorous trials are needed to investigate the effectiveness of prehabilitation among other cancer sites and other related effects. The cost-effectiveness of prehabilitation remains unanswered. IMPLICATIONS FOR CANCER SURVIVORS: Providing interventions earlier in the care pathway may lead to better outcomes for patients during survivorship.

High treatment success rate among multidrug-resistant tuberculosis patients in Myanmar, 2012-2014: a retrospective cohort study.

Background: Since 2011, Myanmar has adopted domiciliary care for multidrug-resistant tuberculosis (MDR-TB) patients and implemented several patient-support measures such as community-based directly observed treatment, nutritional support and financial incentives for patients and providers. We assessed treatment outcomes among MDR-TB patients registered for treatment in the Yangon and Mandalay Regions of Myanmar during 2012-2014 and factors associated with unfavourable treatment outcomes. Methods: We performed a retrospective cohort study involving secondary analysis of routine programmatic data extracted from the electronic MDR-TB treatment registries. We calculated the adjusted risk ratio (aRR) and 95% confidence interval (CI). Results: Of 2185 MDR-TB patients (75% HIV tested, 14% HIV positive with 70% of them receiving antiretroviral therapy), 1746 (80%) were successfully treated (cured and treatment completed) and 20% had unfavourable outcomes (14% died, 3% lost to follow-up, 2% failure and 1% not evaluated). Compared with young patients (<25 y), patients 25-54 y of age (aRR 2.0 [95% CI 1.3 to 2.9]) and >55 y (aRR 3.2 [95% CI 2.1 to 4.8]) were more likely to have unfavourable outcomes. HIV-positive patients (especially not receiving ART; aRR 2.2 [95% CI 1.4 to 3.6]) and patients with 'unknown HIV status' (aRR 1.9 [95% CI 1.5-2.4]) had a higher risk of unfavourable outcomes compared with HIV-negative patients. Conclusions: Treatment success was high and deaths accounted for three-fourths of unfavourable outcomes. Joint care and management of MDR-TB and HIV co-infected patients should be strengthened.

Seronegative conversion in four Neospora caninum-infected cows, with a low rate of transplacental transmission.

Four Neospora-seropositive pregnant cows (prebreeding indirect fluorescent antibody (IFA) titers between 1:400 and 1:1600) were confined and observed until parturition. All cows gave birth to normal calves. Selected tissues were tested for NC by histopathology, immunohistochemical (IHC) and polymerase chain reaction (PCR). Parasite isolation was attempted in vero cell cultures. At parturition, all cows were seronegative at 1:200 and two of four cows had a titer of 1:100 when further tested. Three of four calves were not infected, as determined by negative results of precolostral serology (1:25 cut-off), histopathology, IHC and PCR. One calf was congenitally infected, as shown by the presence of a thick-walled cyst labelled by IHC in its brain, positive PCR of brain and a precolostral IFA titer of 1:100. It was concluded that NC antibody titers may drop or convert to seronegative status in chronically infected cows by the time of parturition and this finding in four of four cows indicates that this could be a common occurrence. Similarly, the finding of an infected calf with a low antibody titer indicates that precolostral serology may not be a fool-proof means of identifying calves with congenital Neospora caninum infections. These findings call into question conclusions of other studies that have estimated rates of congenital transmission of this parasite based on serological tests at calving. This study is the first confirmed report of congenital NC infection in a calf in Thailand.

Scalable quantum memory in the ultrastrong coupling regime.

Circuit quantum electrodynamics, consisting of superconducting artificial atoms coupled to on-chip resonators, represents a prime candidate to implement the scalable quantum computing architecture because of the presence of good tunability and controllability. Furthermore, recent advances have pushed the technology towards the ultrastrong coupling regime of light-matter interaction, where the qubit-resonator coupling strength reaches a considerable fraction of the resonator frequency. Here, we propose a qubit-resonator system operating in that regime, as a quantum memory device and study the storage and retrieval of quantum information in and from the Z2 parity-protected quantum memory, within experimentally feasible schemes. We are also convinced that our proposal might pave a way to realize a scalable quantum random-access memory due to its fast storage and readout performances.

Plasmodium falciparum: sensitivity in vivo to chloroquine, pyrimethamine/sulfadoxine and mefloquine in western Myanmar.

In Rakhine State, on the western border of Myanmar, the efficacy of chloroquine (CQ) and pyrimethamine/ sulfadoxine (PS), the current treatments for uncomplicated Plasmodium falciparum malaria in this area, was evaluated in an open comparative study of 289 patients, stratified prospectively into 3 age groups. Chloroquine treatment was associated with more rapid clinical recovery (P = 0.03), but the overall cure rates were worse than for PS treatment; failure to clear parasitaemia or recrudescence within 14 d occurred in 72% (102/141) of cases treated with CQ compared to 47% (69/148) of those who received PS (P < 0.0001, adjusted for age). Failure rates at day 28 increased to 82% (116/141) in the CQ group and 67% (99/148) in the PS group (P = 0.003). The risk of treatment failure was significantly higher in children under 15 years old than in adults for both CQ (relative risk [RR] = 2.6; 95% confidence interval [95% CI] 1.3-5.2) and PS (RR = 2.2; 95% CI 1.4-3.3). Mefloquine (15 mg base/kg) proved to be highly effective as a treatment for CQ and PS resistant P. falciparum; only 2 of 75 patients (3%) had early treatment failures (< or = day 7), and the overall failure rate by day 42 was 7%. There is a very high level of chloroquine and PS resistance in P.falciparum on the western border of Myanmar, but mefloquine was effective in the area.

Cost effectiveness and cost utility of preventing trachomatous visual impairment: lessons from 30 years of trachoma control in Burma.

AIMS/BACKGROUND: This paper reports on the findings of a cost and effectiveness study of the trachoma control programme (TCP) in Burma. The TCP began in 1964 employing non-surgical interventions (community education and mass treatment with topical antibiotics) and surgical correction of trichiasis. METHODS: Fixed and variable costs of the TCP are assessed over 30 years (1964-93) and apportioned to either surgical or non-surgical interventions. The change in the prevalence of trachoma blindness during this period is used to calculate cases of visual impairment prevented by the TCP. The years of life saved because of premature mortality averted and from living in a handicapped state are added to yield a single measure of utility called handicap adjusted life years (HALYs). RESULTS: The cost effectiveness of the TCP is $54 per case of visual impairment prevented: $193 and $47 for surgical and non-surgical interventions respectively. The cost utility of the TCP is $4 per HALY averted: $10 and $3 for surgical and non-surgical interventions respectively. Results are highly sensitive to the 1965 prevalence of blindness, the choice of discount rate, and the effectiveness of both interventions. CONCLUSIONS: Thirty years of trachoma control in Burma are associated with a remarkable decline in trachomatous blindness. Both surgical and non-surgical interventions are cost effective means of preventing trachomatous visual impairment. Discussion focuses on methodological limitations and implications for research and policy.

Neospora caninum seroprevalence in dairy cattle in central Thailand.

The seroprevalence, in dairy cattle, of antibodies to Neospora caninum, the relationship between seropositivity and age (heifer versus cow), the relationship of herd infection with herd size and the relationship of herd infection with the presence of dogs on the farm were studied. The study involved 549 cows and 82 dogs in 59 dairy herds in Nakhon Pathom, Thailand. A competitive enzyme-linked immunosorbent assay (cELISA) with NC-specific monoclonal antibody was used to detect the NC antibodies in the sera. Individual and herd seroprevalence of NC were 5.5% (30/549) and 34% (20/59), respectively. No significant relationships between NC seropositivity with the age of the cows (heifer versus cow; P > 0.05) and between herd infection and the presence of dogs on the farm (P > 0.05) were found. Herd size significantly affected herd infection (P < 0.05) with higher infection in large than small herds (> or = 21 versus < or = 20 cows). Of 12 cows with a history of abortion, one was seropositive to NC. The seroprevalence of NC antibodies in dogs was 1.2% (1/82). This is the first NC seroprevalence study in dogs in Thailand. It was concluded that Neospora infection was more common at the herd level rather than the individual level in Thailand and the presence of dogs on the farm was not related to the level of herd infection. Caution should be taken in the interpretation of serological tests from the farm dogs.

The prevalence of Enterocytozoon bieneusi in acquired immunodeficiency syndrome (AIDS) patients from the north west of England: 1992-1995.

Microsporidia are increasingly being recognised as important enteric pathogens in patients with advanced human immunodeficiency virus (HIV) disease, i.e. acquired immunodeficiency syndrome (AIDS). The aims of this study were to investigate the frequency of detection of microsporidia associated with diarrhoea in patients with advanced HIV disease in the north west of England, and to determine the species involved and their prevalence. During the period from April 1992 to the end of December 1995, chronic diarrhoea in 88 patients in the late stage of HIV disease was investigated. Duodenal biopsies, duodenal aspirates or jejunal biopsies were received from 38 patients, and stool samples from 63 patients, as part of the routine investigation of possible causes of diarrhoea in these patients. Biopsies and aspirates were examined by thin-section electron microscopy (EM), and stool samples were examined by epi-fluorescence microscopy after staining with Calcofluor. Putative stool positives were confirmed by transmission electron microscopy. CD4-lymphocyte counts were available from all patients who provided samples. Nine out of 63 patients (14.3%) were found to be excreting microsporidial spores on stool examination. The species was confirmed as Enterocytozoon bieneusi. The mean CD4-lymphocyte count for this group was 37 x 10(6)/L (normal range 517-1677 x 10(6)/L). Three out of 38 biopsy specimens (7.9%) were also found to be infected with this microsporidian. The mean CD4-lymphocyte count for this group was 72 x 10(6)/L. Encephalitozoon intestinalis was not found in any samples examined. The prevalence of microsporidial infection in AIDS patients in the north west of England appears to be similar to that of patients in London, but less than that reported in studies from other developed countries.

Parietal cell antibody identified by ELISA is superior to immunofluorescence, rises with age and is associated with intrinsic factor antibody.

Parietal cell antibody is a marker for autoimmune gastritis. With identification of gastric H/K ATPase as its molecular target, ELISAs have been introduced. We compared performance of ELISA with immunofluorescence in a retrospective and prospective sera set and correlated the results with intrinsic factor antibody. In 138 retrospective sera selected for positivity or negativity for intrinsic factor antibody, 87 reacted with gastric H/K ATPase by Euroimm ELISA but only 62 reacted by immunofluorescencence.. Similar results were obtained with Inova ELISA with 78 positives that were also positive by Euroimm ELISA. In 161 prospective sera, 29 sera tested positive by ELISA compared to 24 by immunofluorescence. ELISA positive but immunofluoresnce negative sera are bona fide positives because a representative set of 16 sera reacted with both 95kD α and 60-90kDß subunits of gastric H/K ATPase. ELISA values rose with age regardless of whether immunofluorescence tests were positive or negative. Of 53 sera containing antibody to intrinsic factor, 46/53 (87%) reacted to gastric H/K ATPase by ELISA. Taken together, the data indicates an enhanced detection rate by ELISA over immunofluorescence and validates it as a robust diagnostic assay for parietal cell antibody. As parietal cell antibody marks asymptomatic autoimmune gastritis that may progress to end stage gastric atrophy and haematological complications, and as autoimmune gastritis is associated with autoimmune thyroiditic and type 1 diabetes mellitus, early detection of parietal cell antibody by a sensitive ELISA will enable early follow-up of at risk subjects.

Fluvastatin downregulates VEGF-A expression in TNF-α-induced retinal vessel tortuosity.

PURPOSE: To investigate the effect of tumor necrosis factor alpha (TNF-α) on the mouse retinal vasculature, function, and expression of vascular endothelial growth factor-A (VEGF-A) in the retina and retinal pigment epithelium (RPE) and to evaluate the protective effect of statin therapy (fluvastatin) on retinal vascular and functional changes. METHODS: A single intravenous injection of murine TNF-α (8 µg/kg body weight) was administered to one group of mice (TNF group). In the second group of mice (TNF+Statin group), a single dose of TNF-α was followed by 28 days oral medication of fluvastatin (10 mg/kg/d), and an equivalent volume of saline was administered to the third group (Control group). After 28 days, electroretinography (ERG) and fundus photography were performed. Eyes were collected for cell and molecular studies. Transcript levels of VEGF-A in retina and RPE were quantified using real-time polymerase chain reaction, and protein expression was analyzed by Western blot and immunostaining. RESULTS: TNF-α-injected mice showed retinal vessel tortuosity, structural change, and altered retinal function. Fluvastatin-treated mice exhibited retinal vascular, structural, and functional changes almost similar to those of the control group. VEGF-A expression was significantly upregulated in the retina and RPE of TNF-α-injected mice, and this was significantly downregulated in fluvastatin-treated mice. CONCLUSIONS: This study shows that the TNF-α-induced inflammatory process results in the alteration of retinal microvasculature and function, and fluvastatin could be a potential therapy for treating/preventing retinal microvascular or inflammatory complications.

Effect of sugars on characteristics of Boer goat semen after cryopreservation.

In order to improve Boer goat semen quality during cryopreservation process, the influence of sugar supplementation on semen characteristics of sperm were investigated. Three experiments were carried out to investigate the effect of (a) addition of two monosaccharides (fructose and glucose) and two disaccharides sugars (trehalose and sucrose) (b) sugar combination (fructose and trehalose, sucrose and trehalose, glucose and trehalose), and control (glucose without trehalose) (c) different concentrations of trehalose on cryopreservation using Tris based extender. The total motility, forward motility, viability, normal spermatozoa, acrosome integrity and membrane integrity were assessed subjectively. Differences were not detected among monosaccharides, but glucose increased (P<0.05) sperm forward motility in post-thaw goat semen compared to trehalose or sucrose supplementation. Semen quality did not differ (P>0.05) among disaccharide sugar supplementation. Combination of glucose and trehalose significantly improved the characteristics of Boer spermatozoa after cryopreservation (P<0.05). Supplementation of trehalose (198.24mM) into the glucose extender significantly increased total motility, forward motility, live spermatozoa, acrosome integrity and membrane integrity following cryopreservation (P<0.05). In conclusion, glucose had the better ability to support Boer sperm motility and movement patterns. Combination of monosaccharide (glucose) and disaccharide (trehalose) improved semen quality following cryopreservation. Trehalose supplementation at the concentration of 198.24mM to the glucose extender conferred the greater improvement of semen quality for Boer semen cryopreservation.

Acute suppurative thyroiditis.

A 25 year old woman suddenly developed pain in a neck mass which had been present for 10 years. Aspiration of a large cyst revealed by ultrasonography produced blood stained fluid from which E. coli was subsequently grown. Acute suppurative thyroiditis is the least common inflammation of the gland, and E. coli infection has been reported only once before in the past decade. A technetium scan is helpful in distinguishing acute from subacute thyroiditis.

Interaction between gabaergic and opioid pathways in the regulation of gonadotropin secretion in males.

The effects of naloxone infusion given together with an infusion of LRH on gonadotropin secretion, were studied in 6 normal male volunteers before and after pretreatment with the GABA-transaminase inhibitor, valproic acid. In concordance with previous studies, naloxone infusion augmented the LRH-stimulated secretion of LH. Baseline serum LH concentrations were not significantly different after valproic acid pretreatment compared to control values. Similarly, valproic acid pretreatment failed to blunt the naloxone-augmented LRH-stimulated secretion of LH. Our data suggest that the previously reported animal studies on the central suppressive effect of GABA on endogenous LRH release is less prominent than the suppressive effect of opioidergic regulatory mechanisms in the human male.

The renin-angiotensin system in hypothyroidism of short duration.

In six hypothyroid patients (2 male, 4 females, ages 22 through 59 years), plasma renin activity (PRA) and aldosterone (Aldo) were measured when the patients were euthyroid on levothyroxine therapy and one month after the therapy was stopped. Colonic mucosal potential differences were measured during the hypothyroid and euthyroid stages, and catecholamine sensitivity was determined by the blood pressure response to infused norepinephrine. Significant differences were observed in the PRA and aldosterone concentrations which were 4.1 +/- 2.5 ng/ml/h and 9.4 +/- 5.9 ng/dl, respectively in the hypothyroid stage and 6.9 +/- 2.3 ng/ml/h and 15.2 +/- 7.3 ng/dl, respectively when the patients were made euthyroid. The colonic mucosal potential differences (which reflect increased endogenous mineralocorticoid activity), became more electronegative after correction of hypothyroidism (-16.8 +/- 7.5 mV vs -32 +/- 18.2 mV; P less than 0.04) concentrations. Statistically significant decreases in norepinephrine pressor effects were observed in hypothyroid patients when compared to the euthyroid state (7.4 +/- 2.3 vs 10.9 +/- 1.9 micrograms/ng/min; P less than 0.01). It is concluded that patients with hypothyroidism have a hormonal pattern reminiscent of "low renin hypertension", and exhibit decreased sensitivity to catecholamines. Such changes are corrected when the patients become euthyroid on levothyroxine therapy.

Control of trachoma and prevention of blindness in rural communities in Burma.

Trachoma was identified as the single most important cause of blindness in central Burma in a study carried out in 1961-1962. Control measures started in 1964 considerably reduced the degree of endemicity and severity of the disease in the areas treated. According to recent simplified criteria of evaluation, the prevalence of active trachoma has been reduced by more than 60% and that of active inflammatory disease of moderate and severe intensity from 7.4% to 1.8% of the active cases. A reduction in the risk of becoming infected is evident from changes that have occurred among the younger age groups.The experience acquired by the trachoma control project in central Burma-covering a population of more than 4 million in 8000 villages-emphasizes the importance of the active participation of the community and the role of local auxiliary personnel. Most of the activities, including surgical repair of trichiasis, are the responsibility of health assistants; their training includes, in addition to the recognition and treatment of patients requiring topical application of antibiotics or surgical repair of trichiasis, the screening and referral to the general practitioner or to the eye specialist of those needing more specialized attention.The results already obtained have made possible a gradual replacement of control activities by a surveillance programme, and their integration into the basic health services. The objectives of the trachoma control programme have been expanded to include the prevention and management of other causes of preventable or curable blindness, with special emphasis on eye injuries and glaucoma.

Immunomodulatory effect of bovine PTH extract on lymphocyte response to plant mitogens.

Human peripheral blood lymphocytes were incubated in the presence of various concentrations of bovine parathyroid hormone extract (PTH) or with PTH plus different concentrations of plant mitogens (PHA, Con-A and PWM) to determine whether PTH can modulate lymphocyte proliferation. Lymphocyte proliferation was assessed by 3H-thymidine incorporation into the lymphocytes after a 72-96 h incubation period. After initial inhibition, PTH stimulated lymphocyte proliferation at concentrations of 0.25-0.5 micrograms/0.2 ml and inhibited 3H-thymidine uptake at concentrations of greater than 1 microgram/0.2 ml. Similar responses were seen when the lymphocytes were incubated with PTH plus PHA. In contrast, PTH inhibited 3H-thymidine uptake by the lymphocytes when the cells were stimulated with Con-A (0.25-2 micrograms/0.2 ml) and PWM (0.25-2 micrograms/0.2 ml). The suppressive effects of PTH were not due to loss of lymphocyte viability as determined by trypan blue exclusion. It is speculated that the PTH mediated immunomodulatory effect on peripheral blood lymphocytes may be due to PTH itself or to some other factor(s) in the extract. In view of the common embryonic origin of the parathyroid glands and the thymus, the possibility that thymic-like hormones may be involved in the immunomodulatory process cannot be excluded.