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Biomedical subjects

J G Schmidt

Publications and source records attributed to J G Schmidt.

At least 19 recordsLinked to original sources
PubMed2000

Pharmacologic treatment of cognitive deficits and hypersexuality due to "shaken-baby syndrome".

OBJECTIVE: To describe the clinical effects of amantadine and propranolol in an agitated pediatric patient with cognitive deficits, hyperactivity, and hypersexualism secondary to "shaken-baby syndrome." BACKGROUND: Patients with shaken-baby syndrome can present with cognitive and behavioral impairments. CASE: A 9-year-old girl presented with cognitive impairments secondary to shaken-baby syndrome at 3 weeks of age. She was receiving many medications, including dextroamphetamine, methylphenidate, and clonidine, that were not effective in improving her cognitive status or decreasing her hypersexuality. She was weaned from stimulants and clonidine and prescribed amantadine 100 mg bid with improvement of attention, concentration, and cognition, although hypersexuality remained. She was then started on propranolol 10 mg tid and a gradual increase to 40 mg tid with amelioration of hypersexuality and hyperactivity and no unwanted effects noted. Self-weaning of propranolol was associated with the return of hypersexuality. The combination of amantadine and propranolol led to improvement of cognition and behavior, especially intellectual functioning and appropriate socialization with peers, respectively. CONCLUSION: Cognitive deficits and hypersexuality with hyperactive features due to shaken-baby syndrome may respond to the drug regimen of amantadine and propranolol.

Adrenergic beta-Antagonists↗
PubMed1999

[Evidence-based medicine: modern scientific methods for determining usefulness].

For quite some time, clinical epidemiology has introduced the art of critical appraisal of evidence as well as the methods of how to design sound clinical studies and trials. Almost unnoticed by most medical institutions a new hierarchy of evidence has emerged which puts well thought out trials, able to document unbiased treatment benefit in terms of patient suffering, above pathophysiological theory. Many controlled trials have shown, in the meantime, that the control of laboratory or other kind of pathologies and the correction of anatomical abnormalities do not necessarily mean a benefit for the patient. Concepts relating to this dissection of evidence include: Surrogate fallacy ("cosmetics" of laboratory results or ligament or cartilage "cosmetics" in surgery), confounding (spurious causal relationships), selection bias (comparison with selected groups) as well as lead-time bias (mistaking earlier diagnosis as increase of survival), length bias (overlooking differences in the aggressiveness of diseases as determinants of disease stage distributions) and overdiagnosis bias (mistaking the increasing detection of clinically silent pathologies as improvement of prognosis). Moreover, absolute instead of relative risk reduction needs to be used to measure patient benefit. The incorporation of decision-analysis and of the concepts or clinical epidemiology will improve the efficiency and quality of medicine much more effectively than the sole focus on technical medical performance. Evidence based medicine is the systematic and critical appraisal of medical interventions, based on the understanding how to avoid the fallacies and biases mentioned.

Adult↗
PubMed1999

Cost reduction with successful implementation of an antibiotic prophylaxis program in a private hospital in Ribeirão Preto, Brazil.

OBJECTIVE: To describe the implementation and results of a perioperative antibiotic prophylaxis (PAP) program. DESIGN: A protocol for correct use of PAP was implemented in December 1994. For selected months we measured the PAP protocol compliance of a random sample of clean and clean-contaminated procedures and calculated the cost of incorrect use of PAP. SELLING: A 180-bed general hospital in Ribeirão Preto, Brazil. RESULTS: The cost of unnecessary PAP in the obstetric and gynecologic, cardiothoracic, and orthopedic services dropped from $4,224.54 ($23.47/procedure) in November 1994 to $1,147.24 ($6.17/procedure, January 1995), $544.42 ($3.58/procedure, May 1995), $99.06 ($0.50/procedure, August 1995), and $30 ($0.12/procedure, March 1996). In November 1994, only 13.6% of all surgical procedures were done with correct use of PAP, compared to 59% in January 1995, 73% in August 1995, 78% in March 1996, 92% in November 1996, and 98% in May 1997. CONCLUSIONS: Incorrect PAP use wastes resources, which is a particular problem in developing countries. Our program is simple and can be implemented without the use of computers and now is being adopted in other hospitals in our region. We credit the success of our program to the commitment of all participants and to the strong support of the hospital directors.

Adult↗
PubMed1997

Information transfer from DNA to peptide nucleic acids by template-directed syntheses.

Peptide nucleic acids (PNAs) are analogs of nucleic acids in which the ribose-phosphate backbone is replaced by a backbone held together by amide bonds. PNAs are interesting as models of alternative genetic systems because they form potentially informational base paired helical structures. Oligocytidylates have been shown to act as templates for formation of longer oligomers of G from PNA G2 dimers. In this paper we show that information can be transferred from DNA to PNA. DNA C4T2C4 is an efficient template for synthesis of PNA G4A2G4 using G2 and A2 units as substrates. The corresponding synthesis of PNA G4C2G4 on DNA C4G2C4 is less efficient. Incorporation of PNA T2 into PNA products on DNA C4A2C4 is the least efficient of the three reactions. These results, obtained using PNA dimers as substrates, parallel those obtained using monomeric activated nucleotides.

Chromatography, High Pressure Liquid↗
PubMed1997

Information transfer from peptide nucleic acids to RNA by template-directed syntheses.

Peptide nucleic acids (PNAs) are uncharged analogs of DNA and RNA in which the ribose-phosphate backbone is substituted by a backbone held together by amide bonds. PNAs are interesting as models of alternative genetic systems because they form potentially informational base paired helical structures. A PNA C10 oligomer has been shown to act as template for efficient formation of oligoguanylates from activated guanosine ribonucleotides. In a previous paper we used heterosequences of DNA as templates in sequence-dependent polymerization of PNA dimers. In this paper we show that information can be transferred from PNA to RNA. We describe the reactions of activated mononucleotides on heterosequences of PNA. Adenylic, cytidylic and guanylic acids were incorporated into the products opposite their complement on PNA, although less efficiently than on DNA templates.

Dimerization↗
PubMed1993

[The effect of lowering cholesterol on mortality].

There is little doubt about the validity of the lipid hypothesis as a pathogenetic theory for atherosclerosis. However, this theory does not allow the conclusion that cholesterol-lowering treatment is necessarily beneficial in practice. As a consequence of the probabilistic nature of risk factors, the classification of plasma cholesterol levels into "normal" and "pathological" can be misleading in clinical practice. The potential benefit of cholesterol-lowering treatment is a direct function of the overall coronary risk, more or less independently of plasma cholesterol. Therefore, plasma cholesterol is of clinical significance only in patients with established CHD and a high overall risk of infarction. Total mortality has been prospectively included as one end-point in addition to infarct mortality in the many intervention studies on cholesterol-lowering. Meta-analyses of these studies show a non-significant decrease in infarct mortality through cholesterol-lowering drug treatment, with a concomitant, highly significant increase in non-infarct mortality. Lowering cholesterol in asymptomatic persons and in coronary patients with a relatively low risk of infarction results in a significant increase in total mortality. Only in a very small group of coronary patients with a very high risk of myocardial infarction, due to the presence of several additional risk factors, may cholesterol-lowering treatment be beneficial.

Anticholesteremic Agents↗
PubMed1993

Does routine ultrasound scanning improve outcome in pregnancy? Meta-analysis of various outcome measures.

OBJECTIVE: To evaluate the effectiveness of routine ultrasound scanning in pregnancy by a meta-analysis of various outcome measures. DESIGN: Meta-analysis of randomised controlled trials evaluating the effect of routine ultrasound scanning on perinatal mortality and morbidity. Live birth rate (that is, live births per pregnancy) is included as a measure of pregnancy outcome in addition to the conventional perinatal mortality. SUBJECTS: 15,935 pregnancies (7992 in which routine ultrasound scanning was used and 7943 controls with selective scanning) from four randomised controlled trials. MAIN OUTCOME MEASURES: Perinatal mortality, live birth rate, rate of miscarriage, Apgar score < 7 at 1 minute, and number of induced labours. RESULTS: The live birth rate was identical in both screening and control groups (odds ratio = 0.99; 95% confidence interval 0.88 to 1.12) although the perinatal mortality was significantly lower in the group who had routine ultrasonography (0.64, 0.43 to 0.97). Differences in perinatal morbidity between the two groups as measured by the proportion of newborn babies with Apgar score < 7 at 1 minute were not significant (1.05; 0.93 to 1.19). CONCLUSION: Routine ultrasound scanning does not improve the outcome of pregnancy in terms of an increased number of live births or of reduced perinatal morbidity. Routine ultrasound scanning may be effective and useful as a screening for malformation. Its use for this purpose, however, should be made explicit and take into account the risk of false positive diagnosis in addition to ethical issues.

Abortion, Spontaneous↗
PubMed1990

The epidemiology of mass breast cancer screening--a plea for a valid measure of benefit.

The present paper analyses the epidemiologic effects of mass breast cancer screening. Mass mammography may possibly achieve a breast cancer mortality reduction in relative risk terms. However, this does not necessarily represent a net benefit. It is argued that the benefits and adverse effects of a screening programme must be measured in terms of absolute risks. According to this measure, the mortality reduction achieved by a mass breast screening programme is only one death per approx. 15,000 women-years. Many thousands of mammograms are needed to prevent one cancer death, and for each woman who can derive a direct benefit in terms of a prevented breast cancer death, hundreds of women have to suffer the anxiety of a positive screening mammography. Moreover, it is possible that adverse effects of breast cancer screening may contribute to mortality from other causes. Even with the assumption that screening can save lives, the net health effect of mass breast cancer screening is questionable and appears to be rather detrimental. It may be an error to recommend mass breast screening.

Adult↗
PubMed1989

[Long-term follow-up of deterioration of the visual field in visual acuity in retinitis pigmentosa].

The first part of this presentation is devoted to the problem of determining the precise time of onset of retinitis pigmentosa (RP). For the purpose of this discussion we will stay with the definition of the beginning of RP as that date on which the decrease in dark adaptation is first noticed, rather than visual field loss, which is subject to even greater uncertainty. The cases selected demonstrate that the period between the first sign of night-blindness and a noticeable narrowing of the visual field can vary greatly. A latent period of slow progress is followed by marked decrease in visual function. In a third period the area loss proceeds linearly. The course of the disease was observed over periods of up to 16 years using the Goldmann perimeter. Several stages of visual field deterioration are presented over periods of up to 65 years. The mode of visual field loss depends on the diameter of the test objects employed.

Adult↗