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Biomedical subjects

S Lenz

Publications and source records attributed to S Lenz.

At least 19 recordsLinked to original sources
PubMed2006

[Procedures of temporary wall closure in abdominal trauma and sepsis].

Temporary abdominal closure methods differ mainly between vacuum-assisted and conventional approaches. Each method has its indications. Vacuum-assisted methods seem to be superior especially for trauma indications--in terms of lethality, the possibility of secondary closure during primary hospital stay, and frequency of enterocutaneous fistulas. Skin-only closure might be used as a short-term application (e.g. when damage control closure is needed), and the Bogota bag silo gives space to protruding bowels in pending or manifest abdominal compartment syndrome. Temporary fascial mesh closure enables repetitive laparotomies through the mesh, thus sparing the fascia. For that reason it is to be preferred, especially for its good practicability in clinical situations and on mission abroad.

Abdominal Injuries↗
PubMed2006

[Penetrating injuries to the pelvis].

As criminality and weapon use increase, general and military surgeons are increasingly confronted with penetrating pelvic injuries both at home and on peacekeeping missions. Penetrating injuries to the iliac vascular axis are associated with considerable mortality, and thus the majority of these emergency patients arrive in a state of deep hypovolemic shock. Concomitant bowel injuries are present in one of five cases, resulting in contamination of the damaged area. Surgical options are simple lateral repair, ligation of the veins, temporary shunt insertion, and prosthetic graft interposition in the injured artery. In extremis ligation of the common or external iliac artery may be the only option to save the patient's life. Surgeons must be aware that damage control surgery and related methods may be needed early on to enable patient survival.

Emergencies↗
PubMed2006

[What to do if incompressible bleeding from a stab wound occurs in EMS and ER? Temporary control with a Foley catheter].

Exsanguination plays a key role in avoidable prehospital deaths. As some bleedings from deep stab wounds cannot be stopped with direct compression, the insertion of a Foley catheter can prevent ongoing bleedings. A case report of bleeding from a stab wound in the supraclavicular region is given. The simple measure of careful insertion and blocking of a Foley catheter proved to be a key resuscitative procedure which can be done under any suitable circumstances.

Adult↗
PubMed2005

[German education for treatment of penetrating gut traumata in army service].

On military missions abroad, surgical care for penetrating abdominal injuries differentiates from that given at home. The different conditions in the field usually include a single general surgeon with no further specialists or hospitals to rely upon. Thus a mismatch between treatment capacity and needs can be experienced in mass casualty situations. Therefore the focus is on damage control surgery, getting patients fit for evacuation, and transport home under intensive care if needed. Knowledge of ballistics and explosive devices are adjunct fields of interest, as they improve the understanding and treatment of military injuries. Although these aspects add up to additional training requirements to be met by our surgeons, we are convinced that the new German education standards will allow successful training of future military surgeons.

Abdominal Injuries↗
PubMed2001

Cloning and characterisation of chlorophyll synthase from Avena sativa.

The chlorophyll synthase gene from oat (Avena sativa) was cloned and expressed in Escherichia coli. The deduced amino acid sequence consists of 378 amino acids including a presequence of 46 amino acids. Deletion mutants show that a core protein comprising amino acid residues 88 to 377 is enzymatically active. The sequence of the mature protein shows 85% identity with the chlorophyll synthase of Arabidopsis thaliana and 62% identity with the chlorophyll synthase of Synechocystis PCC 6803. The gene is constitutively expressed as the same transcript level is found in dark-grown and in light-grown seedlings. The enzyme requires magnesium ions for activity; manganese ions can reconstitute only part of the activity. Diacetyl and N-phenylmaleimide (NPM) inhibit the enzyme activity. Site-directed mutagenesis reveals that, out of the 4 Arg residues present in the active core protein, Arg-91 and Arg-161 are essential for the activity. Five cysteine residues are present in the core protein, of which only Cys-109 is essential for the enzyme activity. Since the wild-type and all other Cys-mutants with the exception of the mutant C304A are inhibited by N-phenylmaleimide, we conclude that the inhibitor binds to a non-essential Cys residue to abolish activity. The role of the various Arg and Cys residues is discussed.

Amino Acid Sequence↗
PubMed1999

IL-12 administered during Chlamydia psittaci lung infection in mice confers immediate and long-term protection and reduces macrophage inflammatory protein-2 level and neutrophil infiltration in lung tissue.

Protection against infections with the intracellular bacterium Chlamydia spp. requires Th1-polarized CD4+ T cell immunity. In BALB/c mouse lung infections, immediate innate and nascent Chlamydia-specific immune responses following intranasal inoculation of Chlamydia psittaci strain B577 were modulated by 7-day i.p. administration of murine rIL-12, the initiation cytokine for Th1 immunity. Treatment with IL-12 reduced the severity of chlamydial pneumonia, abolished mortality (37.5% in untreated mice), and significantly reduced numbers of chlamydial organisms in lungs. On day 4 after inoculation, the neutrophil:macrophage ratio in bronchointerstitial pneumonias was 1.96 in untreated mice and 0.51 in IL-12-treated mice. This immediate, IL-12-mediated shift in innate inflammatory phenotype was correlated with a significant reduction of lung concentrations of the neutrophil chemoattractant macrophage inflammatory protein (MIP)-2 (putative murine homologue of human IL-8), monocyte chemotactic protein-1, and TNF-alpha; and a reduction in MIP-1alpha and IFN-gamma, at high-dose infection only, and IL-12-independent IL-10 levels. Chlamydia-specific Ab titers and Ig isotype ratios indicated an IL-12-dependent Th1 shift. Recall responses of IL-12-primed mice to secondary chlamydial lung infection eliminated chlamydiae more effectively and generated a lung cytokine profile conducive to perpetuation of the Th1 memory population. These data support the hypothesis that genetic differences in endogenous IL-12 production and response pathways could determine disease outcomes characterized by poor chlamydial clearance and a purulent inflammatory infiltrate vs effective elimination of chlamydiae in a macrophage-dominated response.

Administration, Intranasal↗
PubMed1999

[Prevention of infection in war wounds].

Medical treatment of injured patients by international missions of non-governmental organisations in crisis areas and out-of-area operations by troops, and also national disasters require special trauma management. Deviations from peacetime surgical guidelines are obligatory because of long-distance medical evacuation, the possibility of gaps in supply and the typical pattern of war injuries. Massive contamination combined with the high risk of infection is one typical attribute of wounds inflicted during a war or a disaster. In contrast to peacetime surgical guidelines, aggressive wound débridement is often needed. Timely and prophylactically prescription of a broad-spectrum antibiotic with a long half-life has great importance in the treatment of these wounds. Suitable antibiotics for these indications are: piperacillin/tazobactam and ceftriazon. Nevertheless the use of antimicrobial agents will only be effective with early surgical débridement.

Antibiotic Prophylaxis↗
PubMed1999

A Danish national cohort of 730 infants born after intracytoplasmic sperm injection (ICSI) 1994-1997.

This national cohort study included all clinical pregnancies obtained after intracytoplasmic sperm injection (ICSI) registered in Denmark between January 1994 and July 1997 at five public and eight private fertility clinics. Laboratory and clinical data were obtained from the fertility clinics. The couples answered a questionnaire regarding the pregnancy and the health of the child (response rate 94%). Data validation was carried out through discharge charts. The mean age of the women was 32.1 years. In 84.2% of couples, male factor was the main reason for performing ICSI, and in 4.8% epididymal spermatozoa were used. The mean number of embryos replaced was 2.3 (range 1-3) and in 95% of cases fresh embryos were transferred. Only 183 women (28.5%) underwent prenatal diagnosis, resulting in 209 karyotypes with seven (3.3%) chromosome aberrations. Six major chromosomal abnormalities (2.9%) and one inherited structural chromosome aberration (0.5%) were found, but no sex chromosome aberrations. The frequency of multiple birth, Caesarean section rate, gestational age, preterm birth, and birth weight were comparable with previous studies. The perinatal mortality rate was 13.7 per 1000 children born with a gestational age of 24 weeks or more. In 2.2% (n = 16) of the liveborn infants, and in 2.7% (n = 20) of all infants, major birth defects were reported by the parents. Minor birth defects were found in nine liveborn infants (1.2%). In conclusion, the results of this study on outcome of ICSI pregnancies are in line with earlier reports, except that no sex chromosome abnormalities were found.

Adult↗
PubMed1996

Abnormal ultrasonic pattern in contralateral testes in patients with unilateral testicular cancer.

Ultrasound examination and biopsy of the nonaffected testis was performed in 78 men with a unilateral testicular cancer. Each testis was measured in three planes and the volume was calculated using the formula of an ellipsoid. The ultrasonic texture of each testis was given a score ranging from 1 to 5 as follows: 1, very regular; 2, slightly irregular; 3, irregular with small echogenic points; 4, very irregular or with coarse echogenic points; and 5, irregular with demarcated areas raising suspicion of tumor. Biopsies were examined for the presence of tubules with carcinoma in situ (CIS), germinative epithelium, Sertoli cell only, and obliterations; the thickness of tubular membranes and the amount of Leydig cells were registered. The mean ultrasonic testicular volume was 12.88 ml (range 3-24 ml), which was smaller than that previously reported for normal men and larger than that previously reported for infertile men. The ultrasonic testicular volume was inversely correlated to the score. Score 4 was given to 46% of the testes (median score, 4), and the score distribution was different from that reported in normal men (median, 2) and in infertile men (median, 3). In all, 9 testes contained CIS tubules, and 8 of these were given score 4; 1 testis with CIS in only 5% of the tubules was given score 3. The predictive value of score 4 for the testis to contain CIS was 22.2%, and the predictive value of a score different from 4 that the testis would not contain CIS was 97.6%. We conclude that a large percentage of contralateral testes in men with unilateral testicular cancer have an abnormal echotexture and that CIS is most likely found in testes given score 4 by ultrasound.

Biopsy, Needle↗
PubMed1996

[Validity of telephone ECG multichannel transmission].

Transtelephonic ECG transmission is an established monitoring system for cardiac patients in many countries around the world with the exception of Germany. This study reports first experiences with a multichannel ECG system using nine leads. This system allows to analyze ECG for ischemic events in addition to cardiac arrhythmias. In this study the reliability of a modified lead registration procedure of the telephonic ECG system David 9 (MAP, München) was compared to conventional 12-lead ECG recording (Mingograph 7, Siemens) in 225 consecutive patients. Comparison was performed using the arm electrodes of the telephonic ECG system (Tel. ECG) within the armpit (group I) or at the wrists (group II). Placing the electrodes at the wrists improved sensitivity and specificity of electrocardiograpic abnormalities to conventional 12 lead ECG (Conv. ECG). Specificity for detection of anterior myocardial infarction was 0.95 (Tel. ECG vs. Conv. ECG), specificity was 1.0. For infero-posterior infarction these relations were 0.94 and 1.0 respectively. ST-segment changes have been detected in the Tel. ECG with 0.93 and 0.89 for specificity and sensitivity. The numbers of arrhythmia analysis were 1.0 and 0.7 for all rhythm disturbances. Detection of atrial fibrillation was less reliable due to short recording time and low amplitude of the transmitted signal. Specificity and sensitivity for detection of ventricular arrhythmias were 1.0 and 0.89. Optimizing the placement of arm electrodes to the wrist instead of armpits as done up to now improved the reliability of the telephonic transmitted ECG. This telephonic ECG system then enables a reliable registration of ischemic and arrhythmic events.

Aged↗
PubMed1995

Pharmacological characterization of heterodimeric NMDA receptors composed of NR 1a and 2B subunits: differences with receptors formed from NR 1a and 2A.

Pharmacological and molecular biological evidence indicates the existence of multiple types of NMDA receptors within the CNS. We have characterized pharmacological properties of receptors assembled from the combination of NR 1a and NR 2B subunits (NR 1a/2B) expressed in transfected cells using both 125I-MK-801 binding assays and electrophysiological measures. Binding of 125I-MK-801 to cells transfected with NR 1a/2B is saturable with a KD of 440 pM. The binding is potently inhibited by ketamine, dextromethorphan, phencyclidine, and MK-801 and is stimulated by low concentrations of magnesium. These properties resemble those of native receptors and receptors produced by NR 1a/2A. However, 125I-MK-801 binding to membranes from cells transfected with NR 1a/2B is inhibited with high affinity by ifenprodil and is stimulated by spermidine, unlike receptors assembled from NR 1a/2A. NMDA-induced currents measured in cells transfected with either NR 1a/2A or NR 1a/2B have pharmacological properties that correlate well with the binding studies. Currents in cells transfected with NR 1a/2B are potentiated by spermidine and blocked with high affinity by ifenprodil, whereas currents in cells transfected with NR 1a/2A are not enhanced by spermidine and are weakly inhibited by ifenprodil. These data suggest that pharmacological heterogeneity in native NMDA receptors may be explained by combinations of different subunits.

Animals↗
PubMed1995

An investigation of the role of Fusarium moniliforme in duodenitis/proximal jejunitis of horses.

Duodenitis/proximal jejunitis syndrome (DPJ) is a small intestinal disease of horses that is associated with depression and copious gastric reflux. Since an infectious cause for DPJ remains unsubstantiated, these studies were designed to investigate the possible role of Fusarium moniliforme toxins in this disease. Fusarium moniliforme was isolated by culturing 2 samples of feed that had been fed to horses with clinical signs of DPJ. These isolates (AU 2/3) were subsequently grown concurrently on autoclaved corn and their toxicity evaluated in a feeding trial utilizing horses. Isolates of F moniliforme known to be low and high producers (RRC 415 and MRC 826, respectively) of fumonisin B1 (FB1) were cultured individually on corn and each fed separately to other groups of horses. Control horses were fed autoclaved corn that was not inoculated with fungus. Production of FB1 by isolates RRC 415, MRC 826 and AU 2/3 were 19, 4360 and 1455 ppm, respectively. Each group contained 2 horses and the test diets were prepared by diluting culture material with sweet feed and clean corn. The test diets consisted of control corn that contained < 1 ppm FB1, RRC 415 diluted to < 1 ppm FB1, MRC 826 diluted to 200 ppm FB1, and AU 2/3 culture material diluted to contain 65 ppm FB1 on days 1-10 and 130 ppm on days 11-27. Horses fed either MRC 826 or AU 2/3 had elevated serum gamma-glutamyltransferase after 7 to 21 d exposure and elevated serum L-iditol dehydrogenase activity after 7 to 19 d exposure to test diets.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1994

Resolution, absolute stereochemistry, and pharmacology of the S-(+)- and R-(-)-isomers of the apparent partial AMPA receptor agonist (R,S)-2-amino-3-(3-hydroxy-5-phenylisoxazol-4-yl)propionic acid [(R,S)-APPA].

(R,S)-2-Amino-3-(3-hydroxy-5-phenylisoxazol-4-yl)propionic acid ((R,S)-APPA) is the only partial agonist at the (R,S)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) subtype of excitatory amino acid receptors so far described. In light of the pharmacological interest in partial agonists, we have now accomplished the resolution of (R,S)-APPA. (S)-(+)-APPA (5) and (R)-(-)-APPA (6) were obtained in high enantiomeric purity using (R)-(+)- and (S)-(-)-1-phenylethylamine, respectively, as resolving agents. The absolute stereochemistry of 6 was established by X-ray analysis of 6.HCl.0.25H2O. Compounds 5 and 6 were tested electropharmacologically using the rat cortical wedge preparation and in receptor-binding assays using [3H]-AMPA, [3H]kainic acid, and the N-methyl-D-aspartic acid (NMDA) receptor ligands [3H]CPP, [3H]MK-801, and [3H]glycine. Whereas 6 did not significantly affect the binding of any of these ligands (IC50 > 100 microM), compound 5 revealed affinity for only the [3H]AMPA-binding site (IC50 = 6 microM). In electropharmacological tests, 5 showed full AMPA receptor agonism (EC50 = 230 microM). This effect of 5 was insensitive to the NMDA antagonist CPP but was inhibited competitively by the non-NMDA antagonist NBQX (pKi = 6.30). Compound 6, on the other hand, turned out to be a non-NMDA receptor antagonist, inhibiting competitively depolarizations induced by AMPA (pKi = 3.54), kainic acid (pKi = 3.07), and 5 (pKi = 3.57).

Alanine↗
PubMed1994

GABA-ergic interneurons of the striatum express the Shaw-like potassium channel Kv3.1.

In addition to numerous GABA-ergic efferent neurons, the striatum contains a subpopulation of fast-firing GABA-ergic interneurons characterized by the presence of immunoreactivity for the calcium-binding protein, parvalbumin. Double-label in situ hybridization with digoxigenin- and radiolabelled cRNA probes was performed on striatal sections of adult rats to identify mRNAs expressed by striatal GABA-ergic interneurons. In the dorsolateral striatum, only parvalbumin mRNA-positive neurons expressed the mRNA encoding the potassium channel Kv3.1, a member of the Shaw family of potassium channels with rapid activation and inactivation kinetics, usually found in fast-firing neurons such as the basket cells of the hippocampus. Colocalization of the parvalbumin and Kv3.1 proteins was confirmed by double-label immunohistochemistry. Parvalbumin mRNA-positive neurons expressed very high levels of the mRNA encoding glutamic acid decarboxylase (Mr 67,000: GAD67) in the dorsolateral striatum. A smaller proportion of double-labelled neurons was found in the ventrolateral striatum. A small number of densely labelled neurons for GAD67 mRNA also expressed the mRNA encoding the dopamine D2 receptor, but none expressed detectable levels of the dopamine D1 receptor mRNA. This indicates major differences in the expression of dopamine receptor mRNA in a majority of GABA-ergic interneurons vs. GABA-ergic efferent neurons of the striatum. The results suggest that distinct molecular characteristics are associated with the distinct electrophysiological properties of striatal GABA-ergic neurons.

Animals↗
PubMed1994

The economic considerations in laparoscopic surgery.

There has been increasing concern in the medical, business, and insurance communities and government agencies about the rising cost of health care. Since 1980 the cost of medical care has increased from $280 billion dollars per year to $670 billion dollars in 1990, and was estimated at $900 billion in 1993. Several factors have contributed to this increase, including the high cost of hospitalization and new expensive technology, such as laparoscopic cholecystectomy. This present cost analysis was undertaken to determine the cost variables in laparoscopic cholecystectomy to see if changes in physician, nursing, and administration work activities could decrease the cost of hospitalization. Fifty-four patients who had an uncomplicated elective cholecystectomy during a five-month period in 1993 were assessed in terms of cost components of hospitalization, including nursing unit labor costs, surgery personnel labor costs, supply/instrument cost, and ancillary costs. Nine general surgeons participated in this study, four of whom accounted for 71% of the annual volume of cases. This analysis was performed with the help of Baxter Corporate Consulting, a Division of Baxter Healthcare Corporation. From this study, it was found that the average cost for uncomplicated laparoscopic cholecystectomy patients was $1589 +/- $223. The operating room and supply/instrument component costs were the two largest expenses, accounting for 42% of the total cost. Reimbursement from various insurance agencies were also evaluated, and it was determined that a contract made with a local HMO caused the hospital to lose an average of $443.00 per patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholecystectomy, Laparoscopic↗