Human periodontal ligament cell sheets cultured on amniotic membrane substrate.

OBJECTIVE: Periodontal ligament (PDL) cells and their substrates play key roles in periodontal regeneration. However, there has been no report on the use of amniotic membrane (AM) as a substrate for culturing PDL cells. In the current study, we conducted an analysis of PDL cells cultivated on AM to determine the distribution of factors responsible for maintaining the characteristics of PDL. MATERIALS AND METHODS: Amniotic membrane was obtained from women undergoing cesarean sections, whereas PDL tissue was obtained from human maxillary third molars. The harvested PDL cells were maintained in explant culture for three or four passages, following which they were cultured on AM. RESULTS: After 3 weeks of culture, the PDL cells had grown well on AM. Immunofluorescence showed that these cells were capable of proliferating and potentially maintaining their PDL-like properties. In addition, strong cell-cell adhesion structures, namely desmosomes and tight junctions, were shown to be present between cells. Electron microscopy images showed that the cultured PDL cells had differentiated and proliferated on AM with lateral conjugation and adhesion to AM. CONCLUSION: We conclude that AM may represent a suitable substrate for culturing PDL cells and that PDL cells cultured on AM show sheet formation.

Sensitivity of sleep stages to painful thermal stimuli.

Many modalities of both acute and chronic pain have been shown to disrupt sleep. Any differences in the intensity of thermal noxious stimulus required to produce arousal from stage 2, slow-wave sleep (SWS) and rapid eye movement (REM) sleep is unclear. An assessment of reactions of seven male (age 22 +/- 2.9 years) and three female subjects (age 21.0 +/- 1.0 years) to a range of gradually increasing temperatures was used both when awake and asleep. When awake, subjects assigned five different descriptors to the increasing heat stimulus. During the different stages of sleep, temperatures were increased over the same range as when awake until the subjects aroused from sleep. The possible fluctuations in pain perception due to a time-of-night effect were assessed in awake subjects over a 12-h period from 19:00 to 07:00 hours. During sleep, arousals occurred at significantly higher temperatures during SWS (P < 0.01) and REM sleep (P < 0.05) than during stage 2 sleep. The temperatures causing arousals during SWS and REM sleep were not significantly different and were equivalent to temperatures causing pain tolerance when awake. No changes in pain perception due to time of night were observed. The results show that a higher intensity of thermal noxious stimulus is required to cause arousal from SWS and REM sleep when compared with stage 2 sleep. This would confirm the suspicion that REM sleep and SWS are relatively, and possibly equally, resistant to disruption by noxious stimuli.

Quantitative assessment of IgG antibodies to Helicobacter pylori and outcome of ischaemic heart disease.

Criticisms of serological studies on Helicobacter pylori and ischaemic heart disease (IHD) include: undiagnosed heart disease in live controls; no assessment of severity or outcome of IHD; and qualitative not quantitative measurements of IgG to the bacteria. The aim was to assess quantitatively IgG levels specific for H. pylori (ng ml(-1)) among patients who survived a myocardial infarction (MI) with those who died of IHD. Sera were from four groups: (1) men who survived one MI; (2) men matched for age and socioeconomic background to group 1; (3) individuals who died suddenly of IHD; (4) accidental deaths matched for age and sex to group 3. Levels of IgG to H. pylori increased with age (P<0.005) but were not associated with smoking or socioeconomic groups. There was a correlation between IgG to the bacteria and decreasing socioeconomic levels only among group 1 (P<0.01). IgG levels were higher for subjects who died of heart disease (median=151 ng ml(-1)) compared with survivors (median=88 ng ml(-1)) (P=0.034) and higher for survivors compared with their controls (median=58 ng ml(-1)) (P=0.039). Future serological studies of H. pylori in relation to IHD should be quantitative and severity of disease considered in analyses.

Operative mortality rates among surgeons: comparison of POSSUM and p-POSSUM scoring systems in gastrointestinal surgery.

PURPOSE: The original Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity and the more recent Portsmouth predictor equation for mortality scoring systems were developed to provide risk-adjusted mortality rates in general surgery. The aim of this study was to compare crude and risk-adjusted operative mortality rates among four surgeons using the above scoring systems and assess their applicability for patients scored retrospectively. METHODS: A total of 505 consecutive patients undergoing major gastrointestinal surgery were analyzed; 65 percent underwent colorectal, 27.5 percent underwent upper gastrointestinal, and 7.5 percent underwent small-bowel surgery. The observed:predicted mortality ratios using the Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity and Portsmouth predictor equation for mortality scoring systems were calculated for each surgeon. RESULTS: The actual overall operative mortality rate was 11.1 percent (elective was 3.9 percent, and emergency was 25.1 percent). The Portsmouth predictor equation for mortality equation predicted a mortality rate of 11.3 percent (P = 0.51). However, the Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity scoring system was found to overpredict death by a factor of two: 21.5 percent (P < 0.001). Mortality rates among the four surgeons varied from 7.6 to 14.7 percent but depended on the proportion of elective vs. emergency surgery. The observed:predicted ratio for Portsmouth predictor equation for mortality was close to unity (0.905-1.067) for all surgeons, but it was 0.45 to 0.56 for Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity. CONCLUSION: The Portsmouth predictor equation for mortality equation seems to be a more accurate predictor of mortality in gastrointestinal surgery. It would seem to provide the best choice for analyzing operative mortality rates for individual surgeons, taking into account variation in case mix and fitness of patients even when scored retrospectively. This has important implications for the future assessment of surgeons' clinical standards and the assessment of quality of surgical care.

Detection of pyrogenic toxins of Staphylococcus aureus in sudden infant death syndrome.

It has been suggested that pyrogenic toxins of Staphylococcus aureus are involved in the series of events leading to some cases of sudden infant death syndrome (SIDS). The objectives of the study were to screen tissues from SIDS infants for pyrogenic toxins and to compare incidence of identification of these toxins among these infants from different countries. An enzyme-linked immunosorbent assay (ELISA) and a flow cytometry method were used to screen body fluids and frozen or formalin-fixed tissues for pyrogenic toxins of S. aureus, toxic shock syndrome toxin 1 (TSST), staphylococcal enterotoxins A (SEA), B (SEB), and C1 (SEC). Toxins were identified in tissues of 33/62 (53%) SIDS infants from three different countries: Scotland (10/ 19, 56%); France (7/13, 55%); Australia (16/30, 53%). In the Australian series, toxins were identified in only 3/19 (16%) non-SIDS deaths (chi2 = 5.42, P < 0.02). The flow cytometry method was useful for toxin detection in both frozen and fixed tissues, but ELISA was suitable only for frozen tissues or those fixed for less than 12 months. Identification of pyrogenic toxins in > 50% of SIDS infants from three different countries indicated further investigation into the role the toxins play in cot deaths might result in development of additional measures to reduce further the incidence of these infant deaths.

Bacterial toxins and sudden unexpected death in a young child.

The sudden unexpected death of a six year old child following an upper respiratory tract infection is reported. Laboratory investigations revealed the presence of staphylococcal toxic shock syndrome toxin-1 (TSST-1) in samples of brain tissue. The significance of this finding is discussed.

Homicidal tandem bullet wound of the chest.

An unusual case of a homicidal gunshot wound to the chest is reported in which two bullets were fired in unison as tandem bullets from a handgun. At autopsy, two intact bullets were retrieved from the body of the victim, yet there was only one entrance wound and a single bullet track across the chest wall and thoracic organs. An examination of the weapon and ammunition supported the likelihood of tandem bullets and suggested the probable mechanism for this event. Very few similar cases have been documented.

Deaths among drug abusers in south-east Scotland (1989-1994).

A survey of deaths of chronic drug abusers who came to medico-legal autopsy in the South-east of Scotland revealed a total of 179 fatalities in the six-year period between 1989 and 1994 inclusive. There was an almost linear increase in the number of such deaths reported to the Procurator Fiscal per year over this period, rising from 14 in 1989 to 45 in 1994. The majority of deaths (86%) were seen in males and the peak age at death was in the third decade of life. In the majority of cases (60%) death was deemed to be accidental and most were due to accidental drug overdoses, with methadone being the drug most commonly detected on toxicological analysis. The number of HIV-positive cases peaked in the years 1991 and 1992 with a decline over the subsequent two years.

The influence of ipsapirone, a 5-HT1A agonist, on sleep patterns of healthy subjects.

Ipsapirone is a new pyrimidinylpiperazine ligand specific for 5-HT1A receptors, with potential therapeutic use in affective disorders. Because 5-HT is involved in the regulation of sleep, we investigated the effect of ipsapirone hydrochloride on sleep patterns in 18 normal, healthy subjects of both sexes. Compared to placebo, ipsapirone 5 mg administered by mouth three times daily for 14 days decreased rapid eye movement (REM) sleep duration and, by the tenth day of treatment, began to reduce slow wave sleep (SWS) duration. The decrease in REM sleep occurred in the first 3 h of sleep. The latency to REM sleep was increased from the first night following ipsapirone administration, remained increased throughout the 14 days of administration, and fell to equal latency on placebo immediately administration ended. Subjective assessments of sleep revealed no differences between ipsapirone and placebo. Our experiments confirm a role of 5-HT1A receptors in sleep. The effects of ipsapirone on the sleep patterns of patients with affective disorders still need to be determined.

A comparative morphological and immunohistochemical study of testicular seminomas and intracranial germinomas.

A series of 10 classical testicular seminomas and 10 intracranial germinomas were reviewed and examined using immunohistochemical techniques. In particular, the staining profiles of the tumour cells and the nature of the mononuclear cell infiltrate at the two sites were studied and compared. The tumour cells in eight of the 10 intracranial germinomas and nine of the 10 seminomas exhibited positive staining with placental alkaline phosphatase. Only one intracranial germinoma showed evidence of human chorionic gonadotrophin expression. Tumour cells in all cases at both sites were negative for cytokeratin and vimentin. The lymphocytic infiltrate in both the testicular and intracranial tumours was similar, comprising T-cells and B-cells, the former predominantly. The presence of macrophages and granulomas in tumours at both sites was noted. These findings confirm the high degree of similarity of germinomas of intracranial and testicular origin, and support the hypothesis of a common derivation. We could find no evidence of differentiation of tumour cells at either site.