Anatomy of the lateral antebrachial cutaneous nerve in relation to the lateral epicondyle and cephalic vein

The lateral antebrachial cutaneous nerve (LACN) is the terminal sensory branch of the musculocutaneous nerve supplying the lateral aspect of forearm. Because of its close proximity to the biceps brachii tendon (BBT), the lateral epicondyle (LE), and the cephalic vein (CV), surgery and venipuncture in the cubital fossa can injure the LACN. Measurement data regarding the relative anatomy of LACN are scarce. We, therefore, dissected 96 upper extremities from 26 males and 22 females to expose the LACN in the cubital fossa and forearm. The LACN consistently emerged from the lateral margin of BBT. It then pierced the deep fascia distal to the interepicondylar line (IEL) in 84.4% with mean distances of 1.8 ± 1.1 and 1.2 ± 0.9 cm (male and female, respectively). At the level of IEL, the LACN in all cases was medial to the LE (5.9 ± 1.1 cm male and 5.2 ± 0.9 cm female). Two types of branching were observed: single trunk (78.1%) and bifurcation (21.9%). Asymmetry in the branching pattern was observed in 6 males and 1 female. Concerning the relationship to the CV, the LACN ran medially within 1 cm at the level of IEL in 78.7%. Moreover, in 10 specimens, the LACN was directly beneath the CV. In the forearm, the LACN tends to course medial to the CV. Significant differences in the measurement data between genders but not sides were found in some parameters. These data are important for avoiding LACN injury and locating the LACN during relevant medical procedures.     

Reaction time, impulse speed, overall synaptic delay and number of synapses in tactile reaction neuronal circuits of normal subjects and thinner sniffers

In control subjects, warned auditory reaction time (RT) for a given effector organ was less than the warned visual RT for the same organ. The RT of the circuits between eye or ear or sites of tactile stimulation (SOS) and the index fingers were significantly shorter than that between eye or ear or the same SOS and the right or left big toes. The greater the distance between the SOS and the brain the longer the RT of the response by a given effector organ. The overall signal speed (OASS) from the neck to the index finger was less than that from the neck to the big toe. The OASS from the neck to a given effector was less than that from the toe to the same effector. Sensory nerve impulse speed was slightly faster than motor nerve impulse speed. The overall synaptic delay and estimated number of synapses (ENOS) of simple tactile reaction neuronal circuits of normal subjects did not significantly vary with site of tactile stimulation or effector organ. The mean number of synapses of various tactile reaction neuronal circuits of normal subjects was estimated to be between 69 and 77, which is far greater than the number of synapses in the touch-tactile and motor pathways combined. The overall synaptic delay in the tactile reaction neuronal circuits between SOS and the left and right big toes were significantly lower in sniffers than in control subjects. This may be due to a decrease in either the average synaptic delay, the number of synapses, or both in the tactile reaction neuronal circuits between sites of stimulation and big toes (but not index fingers) in sniffers.     

Anatomy of the superficial peroneal nerve related to the harvesting for nerve graft

The superficial peroneal nerve (SPN) is one of the two main branches of the common peroneal nerve, which become cutaneous nerve on the lateral side of distal leg and dorsum of foot. The use of SPN as nerve graft has been introduced; however, important data regarding the morphometric anatomy of this nerve and its branches, medial and intermediate dorsal cutaneous nerves (MDN and IDN, respectively) to support this application remain incomplete. Eighty-five legs of cadavers were dissected and the branching pattern was classified into Type 1 (penetration of the main trunk of SPN from the deep fascia) or Type 2 (separate penetration of the MDN and IDN). The length of SPN, MDN and IDN from the penetration points until before subsequent branching was measured. In addition, the penetration points were located by referring to the intermalleolar line and the lateral malleolus. Type 1 was found in the majority of specimens independent of gender (71.8%). Asymmetry in the branching pattern was observed in nine cases (20.9%). The average length of the SPN, MDN and IDN without branches was 7.7, 8.1 and 5.5 cm, respectively. The penetration points of the SPN, MDN and IDN were located 5.1, 7.6 and 5.5 cm above the intermalleolar line, respectively. These data are important for using the SPN as a graft.     

Synaptosomal neurotransmitter uptake systems in the retina and brain nuclei of light- and dark-adapted rabbits

High affinity uptake rate for [14C]aspartate and [3H]dopamine by retinal homogenate (H), Pl (outer plexiform layer, OPL), and P2 (inner plexiform layer, IPL) retinal synaptosomal fractions were not significantly different between light- and dark-adapted rabbits. However, there were significant increases in the dark in [3H]gamma-aminobutyric acid high affinity uptake rate by retinal H and P2 but not that of Pl. There was a significantly higher [3H]choline uptake rate by retinal H, Pl and P2 in the dark-adapted compared to light-adapted rabbits, but there was no significant change in this rate for synaptosomal fractions from the lateral geniculate body, superior colliculus, visual cortex (VA I + II), caudate nucleus (CN) and hippocampus (HP). Data obtained in this study, along with reports of others, indicate that the change in retinal neurotransmission functions may not always be parallel with the change in high affinity uptake rates of neurotransmitters by retinal synaptosomal fractions. Data obtained indicate an increase in retinal cholinergic neuronal activities in the dark and indicate that optic nerves are not cholinergic and cholinergic neurons in brain nuclei, such as VA, CN and HP, are not significantly influenced by optic nerve inputs in light and dark conditions.     

Cardiobacterium hominis endocarditis presenting as acute embolic stroke: A case report and review of the literature

We report on a case of endocarditis attributable to Cardiobacterium hominis in a 31-year-old man who presented with acute-onset, left-sided hemiparesthesia. Magnetic resonance imaging of the brain showed acute infarctions in 2 areas of the right cerebral cortex, and a transesophageal echocardiogram revealed vegetation in a previously unrecognized bicuspid aortic valve. The patient completed a 6-week course of ceftriaxone and aspirin, with resolution of the vegetation and neurological complications. Our literature review of C. hominis endocarditis suggests that aortic-valve involvement is associated with high stroke and valve-surgery rates. Favorable outcomes and treatment success are evident with either penicillin or ceftriaxone, in combination with (if indicated) valve surgery in patients with neurological complications.     

Anatomy of the lateral femoral cutaneous nerve related to inguinal ligament, adjacent bony landmarks, and femoral artery

Lateral femoral cutaneous nerve (LFCN) generally emerges from the pelvis behind the inguinal ligament (IL) to the thigh. Because of its proximity to the anterior superior iliac spine (ASIS) and hip joint, the LFCN is prone to injuries during various procedures. Anatomy of this nerve is highly variable among studies. Moreover, measurement data regarding its branches including the differences between genders and sides are still lacking. This study was, therefore, done to clarify these issues. Eighty-five thighs from 43 cadavers of both genders were dissected at the inguinal region. Distances from each branch of the LFCN to palpable landmarks: the ASIS, pubic tubercle (PT) and femoral artery (FA) were measured along the IL. Up to four branches of the LFCN were found; however, the single trunk was the most common form (>65%). The common site of this pattern on the IL was within 2 cm medial to the ASIS but could be present at over 6 cm. The distances in case of bifurcation were mostly comparable to those of the single trunk. In contrast, the values varied considerably in the cases with three or more branches (three cases). Regarding side and gender, asymmetry in the branching pattern was found in one fourth of specimens. However, only some minor differences between genders or sides in the measurement data were seen. These findings suggest that asymmetry and multiple branches of the LFCN should be concerned. The measurement data are also useful for localizing the LFCN with higher accuracy.     

Correlation between positive chronotropic effect and norepinephrine release induced by acetone in the rat right atrium

The effects of acetone on contraction rate and norepinephrine (NE) release of rat right atrium were investigated. Acetone, in the concentration range 10-210 mM increased the atrial contraction rate (ACR) in a dose-dependent manner, but in concentrations exceeding 210 mM, caused a gradual reduction in the ACR from the peak. The positive chronotropic effect of acetone on ACR can be reduced by adding 0.002 mM of propranolol (a non-selective beta 1- and beta 2-adrenergic receptor blocker), or by pretreating the rat with reserpine (an NE depleter) (5 mg/kg body weight, i.p., 24 h prior to experiment). These findings lead to the hypothesis that the increase in ACR induced by acetone may be partly due to an increase in NE release from sympathetic nerve endings in the atrium by acetone. To test this speculative hypothesis, the effect of acetone on [14C]NE + cold NE release from the right atrium, preinoculated with 0.25 microM of [14C]NE + cold NE for 20 min at 35 degrees C, was carried out using a simple technique developed in our laboratory. The acetone (10-1000 mM)-stimulated peak of NE release (pmol/g atrium/min) and summed NE release (pmol/g atrium/5 min) in excess of the basal spontaneous NE release were analyzed. The dose-response curves of the effect of 10-210 mM of acetone on the ACR and the peak of NE release were parallel. However, acetone concentrations above 210 mM caused a gradual drop of the curve of the ACR from its maximum while still enhancing the curve of the NE release. This continued gradually up to an acetone concentration of 500 mM. The atrial NE release reached a maximum at acetone concentrations between 500 and 1000 mM. This indicates that the increase in ACR caused by acetone in the range 10-210 mM may be partly due to an increase in NE release from the sympathetic nerve terminals in the atrium. However, an acetone concentration above 210 mM may be too toxic to the muscle fibers and/or the pacemaker and/or the conducting system, and so even though the NE release is still increasing, it can not enhance the ACR any further. It is generally speculated that the release of NE from the sympathetic nerve endings in the heart induced by the great number of organic solvents and general anesthetics contributes to the cause of tachycardia, arrhythmia and fibrillation of the heart.(ABSTRACT TRUNCATED AT 400 WORDS)     

Clinical experience with exenatide in predominantly Asian and Pacific Islander patients with type 2 diabetes

Exenatide is a new injectable medication for the treatment of hyperglycemia in type 2 diabetes. Due to limited information of exenatide use in Asians and Pacific Islanders (API), we retrospectively reviewed API patients’ responses to exenatide treatment and compared the efficacy and safety of treatment to Caucasian patients. A total of 92 patients (70 API, 21 Caucasians, and 1 Hispanic) with type 2 diabetes were treated with exenatide. In all patients, there was a significant decrease in A1c level, BMI, and weight after 6 months of exenatide treatment (A1c from 8.63 ± 1.46 to 8.23 ± 1.46; P = 0.03, BMI from 34.54 ± 7.07 to 32.14 ± 6.41; P < 0.01, and weight from 215.24 ± 52.04 to 202.50 ± 49.90; P < 0.01 at 95% CI, N = 51). However, differences in mean change of A1c level, BMI, and weight between API and Caucasian patients were not observed at 3 and 6 months of treatment. Side effects and discontinuation of exenatide treatment between API and Caucasian patients were similar. In conclusion, exenatide is an effective anti-hyperglycemic agent in API patients with responses similar to that observed for Caucasian patients.     

Accuracy of the three-window sampling method in morphometric analysis of human sural nerve

Morphometry has an important role in the assessment of sural nerve biopsies as a part of early detection of structural abnormalities in peripheral nerve. Various sampling methods have been used to reduce time and effort needed in the analysis of total nerve fibers but their accuracy remains controversial. We examined the accuracy of three-window sampling method in the morphometric evaluation of human sural nerve biopsies by comparing with the total fiber quantification. Three windows (0.012 mm(2) each) were placed in every possible fascicle in the sections and data from all windows were pooled and analyzed for the number of myelinated axons, myelinated fiber diameter, axon diameter, myelin thickness, g ratio as well as myelinated fiber density. Means and ranges of the data from the two techniques were similar and the agreement was further confirmed by intraclass correlation analysis. These findings indicate that the three-window sampling method can be used to evaluate human sural nerve with accuracy.     

Anatomical variations of the supraorbital, infraorbital, and mental foramina related to gender and side.

PURPOSE: The aim of the study was to examine the different anatomical variations of the supraorbital, infraorbital, and mental foramina related to gender and side. MATERIALS AND METHODS: Measurements were made on 110 adult skulls without mandibles and isolated mandibles. Gender was determined for each skull. Parameters measured bilaterally included the distances from the supraorbital and mental foramina to midline, from the infraorbital foramen to the anterior nasal spine, from the infraorbital foramen to the inferior orbital rim, and from the mental foramen to the inferior rim of the mandible and the angle between the line linking the infraorbital foramen with the anterior nasal spine and horizontal plane. Comparisons were made between genders and sides and statistical analysis was done where appropriate using Student's t test. RESULTS: There were 70 male and 40 female crania. Nature of the 3 foramina was similar between sides and genders. The average distance from the left supraorbital foramen to midline in females was significantly lower than that in males (2.42+/-0.04 versus 2.56+/-0.05). The mean distances from the bilateral infraorbital foramina to anterior nasal spine in females were also significantly lower relative to those in males (3.28+/-0.03 versus 3.48+/-0.03 right and 3.31+/-0.03 versus 3.50+/-0.03 left). There were also considerable differences between sides in the average angle of the infraorbital foramen in both genders. CONCLUSIONS: Differences in several measurements suggest that gender and side should be considered when applying the anatomical variation data to an individual subject.