Biomedical subjects
Publications and source records attributed to J Green.
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OBJECTIVES: To review recent research into psychological aspects of genital herpes and assess possible implications for clinical practice. METHODS: Review of all papers in the field on Medline 1985-96. RESULTS: Much attention has been paid to possible links between stress and recurrent genital herpes. There is no convincing evidence that stress in itself causes recurrences. It may be that recurrences are preceded by a prodromal period of altered mood. Patients with recurrences show considerable stress as a result of the disease, although most individuals eventually adjust psychologically. The impact of social support on adjustment remains unclear. The little evidence available suggests that antiviral treatments can help adjustment and the effects may perhaps outlast the period of active treatment. CONCLUSIONS: Existing research gives some clues to optimal patient management but there is a need for future research to focus much more clearly on clinical issues, particularly on means of alleviating psychological distress and on the impact of antivirals.
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Hypertensive complications are relatively common in pregnancy, particularly in the presence of preexisting renal disease. Although the pathogenesis of such complications is still unknown, recent animal studies have suggested that it may be related to impaired synthesis of nitric oxide (NO). Rats with adriamycin nephropathy develop a "preeclamptic-type" pregnant state characterized by elevated blood pressure, lack of hyperfiltration, and enhanced proteinuria. Preliminary studies with this model have implicated inadequate NO synthesis in the development of preeclamptic-like pregnancy. The aim of the present study was to confirm this hypothesis. Pregnant rats, both normal (PREG) and those with adriamycin nephropathy (AN-PREG), received 100 mg/L N omega-nitro-L-arginine methyl ester PO from the middle of gestation to term (day 11, term approximately 22 days). One group of AN-PREG rats received either L-arginine or D-arginine (2 g/L) from midpregnancy. At term, systolic pressure, mean arterial pressure, urinary metabolites of NO, creatinine clearance, and urinary protein were assessed. At term, compared with virgin rats with adriamycin nephropathy, untreated AN-PREG rats had increased systolic pressure, mean arterial pressure, and proteinuria (mean arterial pressure, 124 +/- 2.5 versus 99.7 +/- 1.6 mm Hg [P < .05]; proteinuria, 434 +/- 58 versus 216 +/- 63 mg/d [P < .05]). Creatinine clearance did not change (1.68 +/- 0.23 versus 1.35 +/- 0.09 mL/min, P = NS). In PREG rats, urinary metabolites of NO increased approximately threefold at term pregnancy compared with control. By contrast, in AN-PREG rats, excretion of urinary metabolites of NO increased only by approximately 1.7-fold (P < .01) versus PREG rats. With the exception of AN-PREG rats, inhibition of NO synthesis with N omega-nitro-L-arginine methyl ester enhanced blood pressure and decreased creatinine clearance but did not influence proteinuria. Excretion of urinary metabolites of NO was similarly inhibited in all rats. In AN-PREG rats, L-arginine normalized blood pressure (91 +/- 2.15 mm Hg) and lowered proteinuria partially but significantly. D-Arginine had no effect. In summary, AN-PREG rats are unable to adequately increase NO synthesis when physiologically required. Correction of this deficit by L-arginine treatment induced a significant clinical improvement.
The mouse MC3T3-E1 cell line is nontumorigenic and undergoes a typical program of osteoblast differentiation in vitro, producing a bone-like mineralized extracellular matrix. We report responses of these cells to dexamethasone (Dex) and 1,25-(OH)2D3 that are in contrast to findings from other osteoblast culture systems. First, chronic exposure of both early- and late-passaged MC3T3-E1 cells to 10(-7) M Dex, initiated during the proliferation period, blocked osteoblast differentiation, in contrast to the enhanced differentiation observed in cultures of fetal rat calvarial-derived cells. Secondly, 1,25-(OH)2D3 did not up-regulate expression (messenger RNA or protein synthesis) of the endogenous mouse osteocalcin (OC) gene. Several lines of evidence are presented that suggest this response is caused by sequence specific properties of the mouse OC vitamin D response element. We also observed both qualitative and quantitative differences in expression of cell growth (histone H2B) and phenotype-related genes (collagen, OC, osteopontin, glucocorticoid receptor, and 1, 25-(OH)2D3 receptor), between pre- and postmineralization stage osteoblasts, in response to 24 h steroid hormone treatment. Our findings in MC3T3-E1 cells are consistent with current concepts of selective influences of 1,25-(OH)2D3 and glucocorticoids as a function of osteoblast maturation. However, the inhibition of osteoblast differentiation by chronic Dex at 10(-7) M and the down-regulation of OC by 1,25-(OH)2D3 are novel observations relevant to species-specific responsiveness of mouse bone-expressed genes to steroid hormones during osteoblast differentiation.
We used gratings of alternating ridges and grooves in a quantitative psychophysical investigation of tactile perception in patients with Parkinson's disease (PD) and age-matched normal controls. The groove width required for threshold discrimination of grating orientation was 25% higher in the control subjects compared to younger individuals studied previously (p = 0.004), indicating a small but significant decline in tactile spatial acuity with age. Relative to age-matched controls, patients with PD showed a twofold increase in the tactile spatial threshold (p = 3.07 x 10(-8), with somewhat greater impairment on the side more affected clinically (p = 0.03). Testing with the forearm prone, as compared to supine, produced a small improvement in the acuity of patients (p = 0.01) but not controls (p = 0.26). PD patients were also impaired in tactually discriminating grating roughness: their difference limens were over three times higher than those of controls (p = 5.74 x 10(-5)) for gratings differing in groove width, and over twice as high (p = 0.0003) for gratings differing in ridge width. We conclude that PD significantly impairs performance on these tactile tasks.
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Two experiments were conducted to assess the role of the yolk sac during the perinatal period (i.e., from embryonic Day 18 through hatch) and until 15 days after hatching. Experiment 1 describes changes in several yolk components. Approximately 70% of the yolk was absorbed during the perinatal period. Moisture, lipid, protein, and carbohydrate fractions were all utilized during this period. In Experiment 2, the age at which set-point physiological levels of several blood metabolites, as well as the magnitudes of these levels, in deutectomized (DT) chicks (surgical ablation of the yolk sac within 1 hr post-hatch) were not different from non-DT controls. Results indicate that the yolk sac plays a central role in the hatching process of chicks, rather than serving as a major metabolic reserve during the neonatal period.
Samples of faeces collected from a party of canoeists involved in a gastroenteritis outbreak were examined by electron microscopy and RT-PCR for evidence of infection with SRSVs. A broadly reactive primer pair was used to detect SRSVs followed by application of genogroup-specific primers to SRSV-positive specimens. Exposure data were collected by means of a questionnaire. SRSVs were detected in 1/4 specimens examined by EM and 3/4 by RT-PCR. Genogrouping, and sequencing of PCR products revealed two distinct strains: a genogroup I strain, related to the Desert Shield virus, and a genogroup II strain, related to the Lordsdale virus to be associated with the outbreak. Exposure data indicated that capsising and eating food before getting changed were associated with an increased risk of gastroenteritis and was consistent with infection following the consumption of contaminated water. This study confirms the greater sensitivity of RT-PCR for the diagnosis of SRSV infections and its utility, when incorporating genogroup-specific primers, in establishing more complex epidemiological data.
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Three hundred and seventy-eight passengers reported gastroenteritis during four cruises in the western Mediterranean on consecutive weeks of 1995. The rate at which cases were reported each day increased on the fourth cruise. The ship's owner commissioned an epidemiological investigation from the PHLS Communicable Disease Surveillance Centre. Cases reported explosive vomiting and diarrhoea, which lasted from 24 hours to five days, and were suggestive of viral gastroenteritis. No food handlers reported illness, but enquiries suggested that some had been ill and treated themselves. No bacterial pathogens were isolated from faecal specimens provided by cases or from water, food, and environmental samples taken from the galley. Small round structured viruses (SRSV) were identified by reverse transcriptase polymerase chain reaction in two faecal specimens and one specimen of vomit from people who became ill during the fourth cruise. SRSV was also identified in one faecal specimen by electron microscopy. Environmental inspection revealed inappropriate food handling, hygiene, and storage. During one 24 hour period no chlorine was detectable in the water. A case control study conducted on the fourth cruise sought details of exposure to various foodstuffs, unbottled water, and various parts of the ship. No significant associations were found between illness and any exposures. The evidence strongly suggested a continuing outbreak of SRSV infection transmitted from person to person. Some passengers remained on board for a second week and could have transmitted their infection to new arrivals. The ship was cleared and disinfected at the end of the fourth cruise in order to interrupt transmission. Fewer than 10 cases presented in each of the fifth and sixth cruises.