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Biomedical subjects

J Jakobsen

Publications and source records attributed to J Jakobsen.

At least 73 records · Page 4Linked to original sources
PubMed1994

Brain metabolism during short-term starvation in humans.

During prolonged starvation, brain energy requirements are covered in part by the metabolism of ketone bodies. It is unknown whether short-term starvation of a few days' duration may lead to reduced brain glucose metabolism due to the change toward ketone body consumption. In the present study we measured the cerebral metabolism of glucose and ketone bodies in nine healthy volunteers before and after 3.5 days of starvation. Regional glucose metabolism was measured by dynamic positron emission tomography using [18F]2-fluoro-2-deoxy-D-glucose. The mean value of K1* in gray and white matter increased by 12% (p < 0.05), whereas k2* and k3* were unchanged compared with control values. Regional glucose metabolism in cortical gray matter was reduced by 26% from 0.294 +/- 0.054 to 0.217 +/- 0.040 mumol g-1 min-1 (p < 0.001). White matter glucose metabolism decreased by 27% (p < 0.02). The decrease was uniform in gray and white matter with regional decreases ranging from 24 to 30%. A determination using Fick's principle confirmed the reduction in glucose metabolism yielding a decrease of 24% from 0.307 +/- 0.050 to 0.233 +/- 0.073 mumol g-1 min-1 (p < 0.05), whereas CBF did not change (0.57 +/- 0.07 vs. 0.57 +/- 0.06 ml g-1 min-1). The global net uptake of beta-hydroxybutyrate increased 13-fold from 0.012 +/- 0.024 to 0.155 +/- 0.140 mumol g-1 min-1 (p < 0.05). Net uptake of acetoacetate and net efflux of lactate and pyruvate did not change significantly during starvation. The present study shows that the human brain adapts to the changes in energy supply as early as 3 days following initiation of starvation, at which time ketone bodies account for approximately one-fourth of the cerebral energy requirements.

Adult↗
PubMed1994

Diabetic neuropathy.

It has been generally accepted that diabetic neuropathy is associated with substantial morbidity and increased mortality, and that aldose reductase inhibitors are of potential therapeutic value, whereas the beneficial effect of strict insulin treatment is questionable. Contrary to these expectations, population-based studies now report only 6% occurrence of severe neuropathy among insulin-dependent diabetes mellitus patients. Also, intensified insulin treatment preserved conduction velocity for 5 years in a large group of insulin-dependent diabetes mellitus patients and reduced neuropathy development by 60%, whereas studies on aldose reductase inhibitors failed to produce any convincing therapeutic effect.

Aldehyde Reductase↗
PubMed1994

Cardiorespiratory reflexes, vibratory and thermal thresholds, sensory and motor conduction in diabetic patients with end-stage nephropathy.

The neuropathic profile was studied in 26 patients with long-standing, insulin-dependent diabetes mellitus and end-stage nephropathy using tests to evaluate large and small nerve fibres and autonomic function. Clinically, 18 patients (69%) has symptoms and signs of peripheral neuropathy, 9 (35%) had symptoms of autonomic involvement. Vibratory sensation was impaired in 20 patients (77%) in the lower limbs and in 6 (22%) in the upper limbs; cold and warm sensation was equally often impaired in the feet and in the hands with no significant difference between patients with and without neuropathy. Heart rate variation was abnormal in 23 patients at rest (88%), in 24 (92%) during deep breathing and during the orthostatic test. Conduction studies revealed abnormalities in two or more nerves in all patients regardless of whether or not they had overt neuropathy clinically. Thus, the applied multimodal tests revealed evidence of impaired function in large or small nerve fibres or both in all patients independent of clinical findings.

Adult↗
PubMed1994

Effect of pancreas and kidney transplantation on the neuropathic profile in insulin-dependent diabetics with end-stage nephropathy.

From a series of 26 diabetics selected for combined pancreas and kidney transplantations 9 died before surgery was scheduled, one died after surgery and 4 rejected the transplants. The effect of pancreas or kidney transplantation or both on vibratory perception and thermal thresholds, various motor and sensory conduction parameters were studied in 9 of the remaining 12 patients. In 6 both the pancreatic and renal grafts were functioning, in 2 the pancreas was rejected, and in 1 the kidney. At an average follow-up of 41 months after surgery, the mean total score of clinical and electrophysiological improvement in 6 patients with successful combined transplantation was 5.5 +/- 1.6 compared with -4.3 +/- 2.5 in 3 patients with one surviving transplant (P < 0.001). Similarly, the average increase in nerve conduction velocity was 5.8 +/- 1.1 m/s in patients with two functioning grafts whereas it decreased 2.9 +/- 0.7 m/s in those with only one (P < 0.001). The quality of life was considered improved in patients with successful outcome of the two organ transplantations in contrast to the statements of those with only one.

Autonomic Nervous System↗
PubMed1994

ELISA-type titertray assay of IgM anti-GM1 autoantibodies.

We report an ELISA-type titertray assay for autoantibodies against the ganglioside GM1. Trays were coated with ganglioside GM1 and reacted with patients' sera; bound IgM was detected with rabbit antibody to human IgM. High-titer serum from a patient was used as calibrator, another patient's serum as the positive control, and the GM1-specific cholera toxin as the control for GM1 coating. Regression curves of serum titers obtained from different patients were linear and parallel. Intra- and interassay CVs were 4.0-7.8% and 5.5-16%, respectively. We detected antibodies at a titer of 1:250 in normal subjects. Analytical specificity of the calibrator serum against GM1 was demonstrated by immune thin-layer chromatography. Anti-GM1 antibodies were increased in patients with chronic inflammatory demyelinating polyradiculoneuropathy (P < 0.002) or multiple sclerosis (P < 0.01). In Guillain-Barré syndrome, preliminary longitudinal studies showed a decrease in anti-GM1 titer that was related to clinical recovery.

Autoantibodies↗
PubMed1994

Comparing ethnic group-specific DAI equations with the standard DAI.

The Standard DAI is an orthodontic index based on public perceptions of dental aesthetics in the USA and is a regression equation linking the relative social acceptability of dental appearance and the objective, physical measurements of ten occlusal traits. It can be used in surveys of need for orthodontic treatment and as a screening tool in public programmes providing orthodontic care. To determine if the Standard DAI could be used internationally, 200 stimuli (photographs of dental configurations) were rated for dental aesthetics by 413 Chinese students, 418 Latvian students and 428 Native Americans. To develop ethnic group-specific DAI equations these ratings were linked by regression procedures to the occlusal trait measurements available for each of the 200 stimuli. Using these equations, group-specific DAI scores were calculated for the 200 stimuli. At all levels on the DAI scale the percentage agreements, sensitivities and specificities ranged from 73 to 100 per cent indicating that the Standard DA can be used without modification to calculate DAI scores among Chinese, Latvians and Native Americans.

Adolescent↗
PubMed1993

The human incisal suture and premaxillary area studied on archaeologic material.

The purpose of this study was to investigate the extent of the incisal suture, the size of the premaxillary area, and the developmental status of the dentition. Sixty-three medieval crania were examined: 30 from children and 33 from adults, including 5 cases with tooth deviations. All crania were photographed at a 1:1 scale. From the photographs the size of the premaxilla and the length of the incisal suture were measured. In addition, the spatial conditions in the anterior region were recorded. The study showed that the main closure of the suture takes place shortly after the crowns of the permanent incisors have attained their final width size. The mean size of the premaxillary area was larger in individuals with interincisal spacing and smaller in individuals with crowding when comparing with normal spatial conditions. In the cases of tooth agenesis the premaxillary areas were markedly reduced.

Adult↗
PubMed1993

Dental health findings in a Native American settlement.

In 1951, A. Dahlberg took casts of 82 children aged 8-17 who lived in the Sac-Fox Settlement near Tama, Iowa. In 1990, the Indian Health Service supported a survey of 44 survivors from the 1951 study. All were contacted and 23 were examined. The findings from this study were compared with findings from similar aged Sac-Fox residents surveyed in 1982, and with the residents of Iowa of a similar age surveyed in 1980. The DMFS score of the 1990 Sac-Fox samples was larger (92.4) than that for the Iowa Survey (75.3). The periodontal findings were similar in the three samples, with one exception, the category 6+mm pockets were seen more frequently in the 1990 Sac-Fox sample (13.0%) than in the 1982 Sac-Fox (8.7%) and 1980 Iowa (2.9%) samples. Mucosal lesions were observed much more frequently in the Sac-Fox 1990 (69.6%) and 1982 (65.2%) samples, compared to the 1980 sample (8.6%). The frequency of totally edentulous persons was also much greater in the Sac-Fox samples, as compared to the Iowa Sample. It appears that the 1982 recommendations for making preventive procedures available to Sac-Fox adults is still appropriate in 1990.

DMF Index↗
PubMed1993

Predicting handicapping malocclusion using the Dental Aesthetic Index (DAI).

The Dental Aesthetic Index (DAI) is an orthodontic index based on socially defined aesthetic standards. The DAI is useful in both epidemiological surveys to identify unmet need for orthodontic treatment as shown by its use by WHO in ICS-II and as a screening device to determine priority for subsidised orthodontic treatment. The purpose of this study was to determine a decision point on the DAI scale that predicts the clinical judgments of orthodontists in separating handicapping from non-handicapping malocclusion. Orthodontists' decisions were available on a sample of 1306 models representing untreated occlusions found in half a million children. DAI scores were calculated for each model. By correlating orthodontists' decisions with DAI scores a cut-off point was established. Agreements between DAI scores and orthodontists' decisions were best at the 86th percentile on the DAI scale. The DAI score of 36 at the 86th percentile yielded an 88 per cent agreement, a specificity of 93 per cent and a sensitivity of 54 per cent. Cases with scores of 36 and higher would be considered handicapping according to the DAI.

Decision Making↗
PubMed1992

The influence of haematocrit and blood glucose on cerebral blood flow in normal and in diabetic rats.

Cerebral blood flow (CBF) was measured at varying haematocrit values in 8 streptozotocin-diabetic and in 7 control rats using the intracarotid 133Xe technique. A hyperbolic relationship between CBF and haematocrit was established for the individual rats in both groups. Diabetic animals showed a preserved CBF response to changes to haematocrit. In 10 normal rats, CBF was measured during acute hyperglycaemia induced by intraperitoneal glucose injection. A significant, inverse correlation was found between CBF and blood glucose. We conclude that the CBF response to changes in haematocrit and thereby in pO2 is preserved in experimental diabetes. Secondly, in acute hyperglycaemia CBF varies inversely with blood glucose, by mechanisms not fully understood.

Animals↗
PubMed1992

A comparison of three methods for estimating dental plaque removal from individual teeth.

The purpose of this study was to determine the efficiency of dental plaque removal, in vitro, by physical force. Of the 3 methods used, turbidity was the most sensitive for measuring microgram amounts of plaque. Air-dried weight and dental plaque imprint assays (DPIA) complemented turbidity measurements by providing a weight standard and a new method for visualizing plaque bacterial structure before the stained imprint was transformed into numerical data. The amount of dental plaque removed from a tooth by physical force can be measured and described as a percentage of the total removable plaque on that tooth.

Analysis of Variance↗
PubMed1992

The influence of halothane on spermatogenesis in surgical patients.

Seventeen male patients delivered a sperm sample before and 80-90 days after halothane anaesthesia, acting as their own control. The sample was tested according to WHO criteria. There was no difference before and after anaesthesia. We conclude that halothane used in normal anaesthetic concentration in combination with nitrous oxide during arthroscopic knee surgery had no certain effect on the quality of sperm.

Adult↗
PubMed1992

Lymph node metastases in the neck from unknown primary tumour.

During a 12-year period a total of 203 patients were referred to the oncologic center of Odense with lymph node metastases in the neck. Routine examinations on admission failed to detect the primary tumour in 37 patients. During follow-up, the primary was revealed in 18 of these patients, and in a further 8 cases it was found at autopsy. The primary was most often located in the head and neck region with a possibility of curative therapy. Patients with small neck node metastases responded well to treatment with neck dissection and radiotherapy, resulting in a 5-year crude survival rate of 53%.

Adenocarcinoma↗
PubMed1992

Unmasking of the hypotensive effect of nifedipine in normotensives by addition of the angiotensin converting enzyme inhibitor benazepril.

OBJECTIVE: To study the pharmacological interaction between a dihydropyridine derivative (nifedipine slow release 20 mg) and inhibition of the renin-angiotensin system (benazepril 10 mg). DESIGN: Single application at intervals of 2 weeks in an open-label three-way cross-over design. SETTING: Institutional pharmacological unit. PARTICIPANTS: Nine healthy male volunteers. MAIN OUTCOME MEASURES(S): Blood pressure and heart rate were recorded in the supine position for 24 h as well as plasma drug levels, plasma angiotensin converting enzyme activity and active plasma renin concentration. RESULTS: Nifedipine increased active plasma renin two-fold and benazepril increased it five-fold. The combination of the two drugs accelerated the increase of active renin during the first 2 h after drug intake. Whereas no hypertensive effect could be detected after nifedipine or benazepril alone, a significant fall in systolic and diastolic blood pressure was observed for up to 9 to 12 h after the combination. The increase in heart rate induced by nifedipine was minimized by the addition of benazepril. There was no interaction between the pharmacokinetics of benazeprilate and nifedipine which would explain these pharmacodynamic effects. CONCLUSION: These results demonstrate that, in normotensive volunteers, the renin-angiotensin system contributes to mask the hypotensive effect of a single oral dose of dihydropiridine. The concomitant administration of a converting enzyme inhibitor discloses the hypotensive effect and limits the baroreflex-mediated increase in heart rate secondary to vasodilation.

Adult↗
PubMed1991

[Immunomodulator therapy of chronic inflammatory demyelinating polyradiculoneuropathy].

A group of 6 patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) was treated with prednisone, azathioprine, plasma exchange and/or intravenous immunoglobulin. Three of the six patients improved during treatment with prednisone and two patients with severe CIDP both showed a remarkable therapeutic response to treatment with intravenous immunoglobulin.

Adjuvants, Immunologic↗
PubMed1991

[Functional endoscopic endonasal sinus surgery. First experiences with a new method].

A material of 46 patients who were treated operatively on account of chronic recurrent sinusitis by functional endoscopic sinus surgery by Messerklinger's method is presented. In 80% the operation was bilateral. As a serious complication, one case of dural lesion occurred. This healed without further complications and without sequelae. Just under 30% experienced slight per- or postoperative complications in the form of haemorrhage and infection. All of the patients participated in a follow-up examination after an average of 13 months' observation. 80-85% stated that they were free from symptoms or had improved after operation. Late complications were insignificant. Half of the patients had synechia formation in the resection area but the presence of synechia was not found to have any significant relationship to the postoperative course. When it is taken into consideration that the first experience with a new method is concerned, the results are considered to be satisfactory. A more extensive patient material with more prolonged observation and experience from other departments are necessary before the employability of the method in the Danish therapeutic system can be assessed.

Adolescent↗