L and D presequence peptides derived from the precursor of F1beta subunit of the ATP synthase inhibit mitochondrial protein import by interaction with import machinery

We investigated the effect of L and D enantiomers of a 25-residue peptide derived from the N-terminal region of the presequence of Nicotiana plumbaginifolia F1beta subunit of the ATP synthase, pF1beta(1, 25), on import into spinach leaf mitochondria. Three in vitro synthesized precursor proteins using different import pathways were used. Import of the precursor proteins of F1beta subunit of the ATP synthase, pre-F1beta, and the alternative oxidase, pre-AOX, required addition of external ATP. whereas the chimeric precursor containing the N-terminal 84 amino acids of the cytochrome b2 precursor protein linked to dihydrofolate reductase, pre-b2(1, 84)-DHFR was not dependent on ATP. Import of pre-F1beta, and pre-AOX was inhibited already at 1 microM and 3 microM concentration of the L and D enantiomers, whereas inhibition of import of pre-b2(1, 84)-DHFR, occurred at concentrations >10 microM of both enantiomers. Binding efficiency of the precursor proteins was not affected by addition of the L and D enantiomers. There was no correlation between inhibition of import of pre-F1beta and pre-AOX and dissipation of membrane potential measured as a decrease of Rhodamine 123 fluorescence quenching. The inhibitory effect of the L and D presequence enantiomers on import of pre-F1beta and pre-AOX was concluded to occur within the outer membrane translocase machinery beyond the initial precursor receptor interaction. Furthermore, the fact that the D enantiomer had the same effect as the natural peptide showed that interaction of the presequence with the import machinery was not dependent on chiral properties of the presequence.

Chemical cleavage of the overexpressed mitochondrial F1beta precursor with CNBr: a new strategy to construct an import-competent preprotein

We have isolated a soluble import-competent 15 kDa N-terminal fragment of the overexpressed Nicotiana plumbaginifolia F1beta precursor of the ATP synthase (N15pF1beta). The isolation was achieved after chemical cleavage, with CNBr, of the insoluble precursor collected in inclusion bodies, followed by purification of the fragment using ion-exchange chromatography. The purity of the final product was estimated to be more than 99%. N15pF1beta contained a presequence of 54 amino acid residues (except for the N-terminal methionine residue) and 82 N-terminal residues of the mature protein. N15pF1beta was shown to be imported into isolated potato tuber mitochondria and to be processed by the isolated mitochondrial processing peptidase (MPP) integrated into the cytochrome bc1 complex of the respiratory chain. Addition of N15pF1beta at micromolar concentrations resulted in the inhibition of import of F1beta precursor and alternative oxidase precursor, synthesized in vitro, into isolated mitochondria as well as the processing of these precursors catalysed by the isolated MPP-bc1 complex. N15pF1beta conjugated via a biotin link to avidin blocked import sites even after the reisolation of mitochondria and inhibited the import of the mitochondrial precursors, indicating that it can be used as a substrate for the generation of a stable translocation intermediate. Our results present a novel procedure for the production of an N-terminal fragment of the F1beta precursor that contains all information necessary for mitochondrial targeting and processing and that can be used for structural and functional studies of the mitochondrial protein import system. This procedure has a general value because it can be used for the production of chemical quantities of any mitochondrial import substrate and presequence peptide.

P50 abnormalities in schizophrenia: relationship to clinical and neuropsychological indices of attention

While the P50 component (50-60-ms latency) of the auditory evoked potential has been reported as abnormal in schizophrenia, few studies have examined the relationship between this abnormality and clinical or neuropsychological measures. To examine these possible relationships, mid-latency auditory evoked potentials were recorded at the CZ recording site of 47 patients with schizophrenia in response to binaural clicks presented at three stimulus rates: 1, 5 and 10/sec. A sub-sample of patients were then divided into high- (n = 15) and low-P50 abnormality (n = 16) groups based on a median split of the P50 amplitude at a rate of 10/sec (a greater amplitude at this rate suggests a greater abnormality in recovery) of the entire sample. Only those patients with complete neuropsychological and clinical data and who were reasonably matched on demographic dimensions were included. A multivariate analysis of variance of 11 neuropsychological function profile scores showed a significant group x global score interaction (Hotelling t = 3.97, p < 0.005). The high-abnormality group had relatively greater deficits for attention profile scores than for the remaining neuropsychological measures. An analysis of global subscores for SAPS and SANS clinical measures revealed a significant difference only for the SANS attention subscale (p < 0.05). The high-abnormality group was rated as more severe on the attention measure. These convergent findings across both phenomenological and neuropsychological measures suggest that abnormalities in P50 recovery may be linked to deficits in attention processes in schizophrenia.

Physiological responses of fathead minnow larvae to rice pesticides

Newly hatched fathead minnow (Pimephales promelas) larvae were exposed for 4 days to two pesticides and ambient receiving waters to simulate conditions in the Sacramento River, California, during the striped bass spawning season which coincides with pesticide use in adjacent rice culture. Carbofuran and molinate were tested at two concentrations: a higher level approximating one-half the LC50 and a level much lower that is similar to that seen in the receiving waters of Colusa Basin Drain. Physiological measurements were made immediately after the exposures and again after a 10-day recovery period in noncontaminated waters. These included growth rate, swimming capacity, response to a mild electric shock, upper and lower lethal temperatures, and activity of acetylcholinesterase in whole-body homogenates. The higher concentrations of carbofuran and molinate caused reductions in swimming capacity, an increased sensitivity to the electric shock, and a reduction in upper lethal temperature. Acetylcholinesterase was reduced in those larvae exposed to the higher levels of carbofuran. In general, the lower levels of pesticide exposure caused no measureable effects nor did exposure to water from Colusa Basin Drain.

Attentional dysfunctions in neuroleptic-naive and neuroleptic-withdrawn schizophrenic patients and their siblings

This study examined attentional deficits in 44 schizophrenic patients (24 neuroleptic-naive and 20 neuroleptic-withdrawn patients) across changes in medication status and clinical state using a 1-9 continuous performance test (CPT) with distractors. Patients' attentional selectivity scores (A') were unchanged from the off-medication to on-medication testings (on average, 6 months later), despite significant improvement in both positive and negative symptoms. Both patient groups had significantly lower A' scores than 44 matched healthy controls at each testing. The nonschizophrenic siblings (n = 15) of these patients made significantly more errors of omission and commission than healthy controls. The results suggest that attentional deficits, as measured by this CPT, appear to measure stable markers of schizophrenia that may be associated with genetic vulnerability to the illness.

Attentional dysfunctions in neuroleptic-naive and neuroleptic-withdrawn schizophrenic patients and their siblings

This study examined attentional deficits in 44 schizophrenic patients (24 neuroleptic-naive and 20 neuroleptic-withdrawn patients) across changes in medication status and clinical state using a 1-9 continuous performance test (CPT) with distractors. Patients' attentional selectivity scores (A') were unchanged from the off-medication to on-medication testings (on average, 6 months later), despite significant improvement in both positive and negative symptoms. Both patient groups had significantly lower A' scores than 44 matched healthy controls at each testing. The nonschizophrenic siblings (n = 15) of these patients made significantly more errors of omission and commission than healthy controls. The results suggest that attentional deficits, as measured by this CPT, appear to measure stable markers of schizophrenia that may be associated with genetic vulnerability to the illness.

Lexical-semantic deficits in two patients with dominant thalamic infarction

Two patients with dominant thalamic infarction, one in the tuberothalamic artery territory, the other in the paramedian artery territory, demonstrated language impairment limited to word retrieval difficulties in spontaneous language and structured naming tasks. Using a cognitive neuropsychological model of lexical processing developed in the study of patients with cortical lesions. We carried out a detailed investigation of their lexical abilities. Both patients demonstrated impairment restricted to oral and written picture naming and oral naming to definition and spared performance on tasks of lexical comprehension, oral word reading, and writing to dictation, as well as syntactic comprehension and production. Naming impairment disproportionately affected lower frequency words, and word substitutions often corresponded to objects that were semantically-related to target words. We propose that our patients' word retrieval impairments reflect a failure of thalamic input to effectively engage the cortical networks subserving lexical semantic processing, leading to degraded levels of activation as the semantic system interfaces with subsequent stages of lexical processing.

Infections after hysterectomy. A prospective nation-wide Swedish study. The Study Group on Infectious Diseases in Obstetrics and Gynecology within the Swedish Society of Obstetrics and Gynecology

BACKGROUND

An increased use of prophylactic antibiotics to avoid postoperative infections in women undergoing hysterectomy has been observed in Sweden. This investigation was performed a) to study the infection rate to enable future evaluation of the effect of prophylactic antibiotic regimens and b) to identify subgroups suitable for intervention.

METHOD

A prospective study comprising all women undergoing pelvic surgery with hysterectomy during a two month period at forty-two Departments of Obstetrics and Gynecology in Sweden. Relevant information regarding the surgical procedure and the postoperative course was included in a standardized form at discharge from hospital and at a follow-up visit 4 to 6 weeks after surgery.

RESULTS

Of the 1060 women included in the study, 23% developed postoperative infections: 9.4% had wound-, cuff-, and/or deep infections, 13% urinary tract infections, and 4% other infections unrelated to the surgical site. Only half of the wound/cuff-/deep infections were diagnosed before discharge from the hospital. Wertheim-Meigs procedures, bleedings per-operatively exceeding 1000 ml, and presence of bacterial vaginosis (BV) were associated with an increased risk of postoperative infections. Among women undergoing abdominal hysterectomy for benign reasons, (n = 159), wound-cuff/deep infection was significantly associated with preoperative BV, i.e. 7 of 28 (25%) vs. 11 of 131 (8%), respectively (relative risk = 3.0, p = 0.01). Infection was associated with prolonged postoperative hospital stay. Antibiotics were given pre- or postoperatively to 236 (22%) of the 1060 women. Reduction in the postoperative infection rate was seen among women undergoing vaginal hysterectomy who were given pre- or postoperative antibiotics.

CONCLUSION

The postoperative infection rate after hysterectomy was clinically significant in this population. Wertheim-Meigs procedures, peroperative bleeding > 1000 ml and BV were identified as risk factors for postoperative infections after hysterectomy.

Physician satisfaction with the development of HMOs in Dane County: 1983-1993

In September 1993, the 1,196 active physicians in Dane County were surveyed to learn their satisfaction with the development of HMOs and comparisons to similar satisfaction surveys in 1986 and 1983. Among the 675 usable responses, 65% reported that they were satisfied or very satisfied with their current work, which is about the same as the 1986 survey when 68% reported that they were satisfied. Other findings suggest support for HMO development in Dane County. Moreover, 66% reported support for the basic principles of the Clinton health system reform plan announced in September 1993.

Neuropsychological functioning in siblings discordant for schizophrenia and healthy volunteers

OBJECTIVE

To determine whether schizophrenics and their nonschizophrenic siblings have a similar pattern of neuropsychological deficit when compared with normal controls.

DESIGN AND PARTICIPANTS

Fifteen probands with schizophrenia, 16 of their nonschizophrenic siblings, and 31 unrelated, demographically balanced, normal individuals underwent evaluation with a comprehensive neuropsychological test battery. All subjects were screened for history of head injury, neurologic illness, major medical conditions, substance use, and axis I psychiatric disorders other than schizophrenia. Probands underwent evaluation twice: once at intake when half had never received neuroleptic medication and the other half had received none for a minimum of 2 weeks, and again at the 2- to 4-week follow-up, after stabilization with neuroleptic medications.

RESULTS

Both schizophrenics and their nonschizophrenic siblings were impaired neuropsychologically compared with normal controls, with the nonschizophrenic siblings' performance intermediate between that of the schizophrenic siblings and the normal controls on all measures of functioning. The shapes of the deficit profiles of schizophrenic patients and their siblings were similar; in patients, verbal memory, abstraction, attention, and language functions were significantly more affected compared with spatial abilities, spatial memory, and sensory-motor functions, with a nonsignificant trend in the same direction in siblings. Cognitive functioning in patients was found to be stable across changes in medication status and clinical state. Four fifths of patients obtained more deviant scores than their nonschizophrenic siblings. Among the sibling group, those with probable and certain diagnoses of schizotypal personality disorder were more impaired compared with those without schizophrenia-spectrum symptoms.

CONCLUSION

These results support the hypothesis that impaired information processing aggregates in the family members of schizophrenics and may serve as an indicator of genetic vulnerability to the disorder. Further work is needed to establish whether particular areas of functioning are selectively impaired in relatives and to determine whether the performance deficits are mediated by structural and/or metabolic disturbances in specific brain regions.

Confrontation naming deficit in dementia of depression

Unlike patients with irreversible dementia, elderly depressed patients with cognitive impairment are thought to have relatively preserved recognition, memory, and language abilities. To test this hypothesis, the authors compared memory and naming performance in elderly hospitalized patients with major depression alone, reversible dementia of depression, or irreversible dementia. All patient groups performed worse than nondemented, nondepressed control subjects on memory tasks. Patients with dementia of depression performed worse than depressed patients with normal cognition on tests of free recall, delayed recall, and verbal delayed memory but not on tests of delayed visual memory. Patients with dementia of depression and patients with irreversible dementia were severely compromised in both speed and accuracy on the confrontation naming task.

Structural brain correlates of emotional disorder in multiple sclerosis

Eighty-seven patients with definite multiple sclerosis (MS) were examined neurologically and administered the Mini-mental State examination (MMS) to assess cognitive disability at the beginning and end of a one-year study. A CT scan was performed in 37. A group of 16 patients with stable spinal cord injuries (SCI) were studied in a similar manner. Of the MS patients, 47% had a mean General Health Questionnaire (GHQ) score in the abnormal range. This was a higher rate than in SCI patients (P = 0.004). Mean depression scores were similar in MS and SCI patients, but MS patients with brain involvement were more depressed than those with cord lesions only (P = 0.05). Depression score was unrelated to functional disability but was correlated with the degree of neurological impairment (P = 0.03). Euphoric patients were more likely to have brain involvement (P = 0.006), to have progressive MS (P less than 0.0001), and to have enlarged ventricles (P = 0.04) and were more impaired cognitively (P = 0.04) than noneuphoric patients. These results suggest that depression in MS patients is partly determined by the presence of brain involvement, but that it is also an emotional reaction to the disorder. Euphoria and cognitive disorder are reflections of brain involvement.

Treating the intoxicated adolescent. A need for comprehensive services

Intoxicated adolescents seen in hospital emergency departments are frequently treated for their immediate complaints, but fail to have follow-up assessments for underlying alcohol/drug abuse and/or psychosocial problems. We undertook a prospective study of 171 acutely intoxicated adolescents (12 to 18 years of age) admitted to the emergency department of the University of Wisconsin Hospital and Clinics, Madison. A comparison group randomly selected from the community demonstrated that the emergency department patients were at a significantly higher risk for alcohol and polydrug abuse and psychological dependency. To adequately serve this potentially high-risk group, follow-up assessment must be done, including the gathering of in-depth information regarding legal, psychosocial, and alcohol/drug use status. This study indicates that the general hospital, with its 24-hour emergency department services and other resources, can play a vital role not only in the crisis management of intoxicated adolescents, but in their follow-up, assessment, and, when indicated, appropriate referral for treatment.

Cervical bacterial flora in infertile and pregnant women

The cervical bacterial flora in early pregnancy, labour, and infertility was assessed qualitatively. The cervix harboured several types of bacteria in both pregnant and infertile women. In the latter group, however, fewer species were found. The incidence of a mixed aerobic and anaerobic flora differed significantly between patient categories as did the frequency with which only aerobic isolates were obtained. There was also a significant difference between patient groups with regard to the incidence of anaerobic isolates. Among the anaerobic bacteria, peptostreptococci and bacteroides species were the dominating ones whereas coagulase-negative staphylococci were the most prevalent aerobic bacteria. Lactobacilli constituted 29--44% of the anaerobic bacteria found in the pregnant cervix and 52% of those found in the infertile cervix. The distribution of different aerobes as well as anaerobes was similar in pregnant and infertile patients.

Changes of bone mineral content during pregnancy and lactation

In order to study changes in the calcium depots of the body during pregnancy and lactation, bone mineral deteminations were performed on fourteen pregnant women and eighteen mothers post partum by X-ray spectrophotomeyry. Pregnant women exhibited a loss in trabecular bone but not in cortical bone when measured once during late first or early second trimester and again one week post partum. Lactating women who nursed less than three months lost mineral during the first three months and than regained it while those who nursed for longer than three months had no losses during six months of study.

The hazards of vacuum aspiration in late first trimester abortions

The incidence of somatic complications in connection with legal termination of pregnancy by vacuum aspiration was analysed in 1,123 hospital patients. Special attention was paid to complication rates in relation to gestational age. It was found that the incidence of major uterine haemorrhage increased with gestational period, being unexpectedly high in the 12th week. When anaesthesia was supplemented with halothane there was a significantly higher incidence of uterine haemorrhage that when this anaesthetic was avoided. The results indicate that strict principles for the operation procedure are mandatory to reduce blood loss and other complications. It is suggested that the end of the 12th week should not be considered as a "magic" time limit for vaccum aspiration but that the policy should aim at early intervention, preferably before the end of the 10th week. In the event of late first trimester abortions or "border line" cases it is of advantage to administer prostaglandin extra-amniotically for pre-operative dilatation of the cervix.